diff --git a/Meta/Lagom/Tools/CodeGenerators/LibWeb/BindingsGenerator/IDLGenerators.cpp b/Meta/Lagom/Tools/CodeGenerators/LibWeb/BindingsGenerator/IDLGenerators.cpp
index b13fcd82dcb..58e40cb637c 100644
--- a/Meta/Lagom/Tools/CodeGenerators/LibWeb/BindingsGenerator/IDLGenerators.cpp
+++ b/Meta/Lagom/Tools/CodeGenerators/LibWeb/BindingsGenerator/IDLGenerators.cpp
@@ -3013,7 +3013,7 @@ JS_DEFINE_NATIVE_FUNCTION(@class_name@::@attribute.setter_callback@)
     if (!cpp_value)
         impl->remove_attribute(HTML::AttributeNames::@attribute.reflect_name@);
     else
-        MUST(impl->set_attribute(HTML::AttributeNames::@attribute.reflect_name@, DeprecatedString::empty()));
+        MUST(impl->set_attribute(HTML::AttributeNames::@attribute.reflect_name@, String {}));
 )~~~");
                 }
 
diff --git a/Tests/LibWeb/TestHTMLTokenizer.cpp b/Tests/LibWeb/TestHTMLTokenizer.cpp
index 39f4fe4dec4..15a01a85b6c 100644
--- a/Tests/LibWeb/TestHTMLTokenizer.cpp
+++ b/Tests/LibWeb/TestHTMLTokenizer.cpp
@@ -61,7 +61,7 @@ using Token = Web::HTML::HTMLToken;
 
 #define EXPECT_TAG_TOKEN_ATTRIBUTE(name, attribute_value, name_start_column, name_end_column, value_start_column, value_end_column) \
     VERIFY(last_token);                                                                                                             \
-    auto name##_attr = last_token->raw_attribute(#name);                                                                            \
+    auto name##_attr = last_token->raw_attribute(#name##_fly_string);                                                               \
     VERIFY(name##_attr.has_value());                                                                                                \
     EXPECT_EQ(name##_attr->value, attribute_value);                                                                                 \
     EXPECT_EQ(name##_attr->name_start_position.column, name_start_column);                                                          \
diff --git a/Userland/Libraries/LibWeb/Bindings/AudioConstructor.cpp b/Userland/Libraries/LibWeb/Bindings/AudioConstructor.cpp
index dbc96297202..bdf4c1d0471 100644
--- a/Userland/Libraries/LibWeb/Bindings/AudioConstructor.cpp
+++ b/Userland/Libraries/LibWeb/Bindings/AudioConstructor.cpp
@@ -46,14 +46,14 @@ JS::ThrowCompletionOr<JS::NonnullGCPtr<JS::Object>> AudioConstructor::construct(
     auto audio = TRY(Bindings::throw_dom_exception_if_needed(vm, [&]() { return DOM::create_element(document, HTML::TagNames::audio, Namespace::HTML); }));
 
     // 3. Set an attribute value for audio using "preload" and "auto".
-    MUST(audio->set_attribute(HTML::AttributeNames::preload, "auto"sv));
+    MUST(audio->set_attribute(HTML::AttributeNames::preload, "auto"_string));
 
     auto src_value = vm.argument(0);
 
     // 4. If src is given, then set an attribute value for audio using "src" and src.
     //    (This will cause the user agent to invoke the object's resource selection algorithm before returning.)
     if (!src_value.is_undefined()) {
-        auto src = TRY(src_value.to_deprecated_string(vm));
+        auto src = TRY(src_value.to_string(vm));
         MUST(audio->set_attribute(HTML::AttributeNames::src, move(src)));
     }
 
diff --git a/Userland/Libraries/LibWeb/Bindings/ImageConstructor.cpp b/Userland/Libraries/LibWeb/Bindings/ImageConstructor.cpp
index 54702eb923d..06ebc87ddb2 100644
--- a/Userland/Libraries/LibWeb/Bindings/ImageConstructor.cpp
+++ b/Userland/Libraries/LibWeb/Bindings/ImageConstructor.cpp
@@ -48,13 +48,13 @@ JS::ThrowCompletionOr<JS::NonnullGCPtr<JS::Object>> ImageConstructor::construct(
     // 3. If width is given, then set an attribute value for img using "width" and width.
     if (vm.argument_count() > 0) {
         u32 width = TRY(vm.argument(0).to_u32(vm));
-        MUST(image_element->set_attribute(HTML::AttributeNames::width, DeprecatedString::formatted("{}", width)));
+        MUST(image_element->set_attribute(HTML::AttributeNames::width, MUST(String::formatted("{}", width))));
     }
 
     // 4. If height is given, then set an attribute value for img using "height" and height.
     if (vm.argument_count() > 1) {
         u32 height = TRY(vm.argument(1).to_u32(vm));
-        MUST(image_element->set_attribute(HTML::AttributeNames::height, DeprecatedString::formatted("{}", height)));
+        MUST(image_element->set_attribute(HTML::AttributeNames::height, MUST(String::formatted("{}", height))));
     }
 
     // 5. Return img.
diff --git a/Userland/Libraries/LibWeb/Bindings/OptionConstructor.cpp b/Userland/Libraries/LibWeb/Bindings/OptionConstructor.cpp
index cd1755d54e6..be599b3d672 100644
--- a/Userland/Libraries/LibWeb/Bindings/OptionConstructor.cpp
+++ b/Userland/Libraries/LibWeb/Bindings/OptionConstructor.cpp
@@ -61,7 +61,7 @@ JS::ThrowCompletionOr<JS::NonnullGCPtr<JS::Object>> OptionConstructor::construct
 
     // 4. If value is given, then set an attribute value for option using "value" and value.
     if (vm.argument_count() > 1) {
-        auto value = TRY(vm.argument(1).to_deprecated_string(vm));
+        auto value = TRY(vm.argument(1).to_string(vm));
         MUST(option_element->set_attribute(HTML::AttributeNames::value, value));
     }
 
@@ -69,7 +69,7 @@ JS::ThrowCompletionOr<JS::NonnullGCPtr<JS::Object>> OptionConstructor::construct
     if (vm.argument_count() > 2) {
         auto default_selected = vm.argument(2).to_boolean();
         if (default_selected) {
-            MUST(option_element->set_attribute(HTML::AttributeNames::selected, ""));
+            MUST(option_element->set_attribute(HTML::AttributeNames::selected, String {}));
         }
     }
 
diff --git a/Userland/Libraries/LibWeb/CSS/CSSStyleDeclaration.cpp b/Userland/Libraries/LibWeb/CSS/CSSStyleDeclaration.cpp
index 4410b685a5e..b45064a3394 100644
--- a/Userland/Libraries/LibWeb/CSS/CSSStyleDeclaration.cpp
+++ b/Userland/Libraries/LibWeb/CSS/CSSStyleDeclaration.cpp
@@ -183,7 +183,7 @@ void ElementInlineCSSStyleDeclaration::update_style_attribute()
     m_updating = true;
 
     // 5. Set an attribute value for owner node using "style" and the result of serializing declaration block.
-    MUST(m_element->set_attribute(HTML::AttributeNames::style, serialized()));
+    MUST(m_element->set_attribute(HTML::AttributeNames::style, MUST(String::from_deprecated_string(serialized()))));
 
     // 6. Unset declaration block’s updating flag.
     m_updating = false;
diff --git a/Userland/Libraries/LibWeb/DOM/Attr.cpp b/Userland/Libraries/LibWeb/DOM/Attr.cpp
index f1444b58ac6..d7625dda036 100644
--- a/Userland/Libraries/LibWeb/DOM/Attr.cpp
+++ b/Userland/Libraries/LibWeb/DOM/Attr.cpp
@@ -115,7 +115,7 @@ void Attr::handle_attribute_changes(Element& element, DeprecatedString const& ol
     }
 
     // 3. Run the attribute change steps with element, attribute’s local name, oldValue, newValue, and attribute’s namespace.
-    element.run_attribute_change_steps(local_name().to_deprecated_fly_string(), old_value, new_value, deprecated_namespace_uri);
+    element.run_attribute_change_steps(local_name(), old_value, new_value, deprecated_namespace_uri);
 }
 
 }
diff --git a/Userland/Libraries/LibWeb/DOM/DocumentLoading.cpp b/Userland/Libraries/LibWeb/DOM/DocumentLoading.cpp
index 2a70a2dc835..07b66a67547 100644
--- a/Userland/Libraries/LibWeb/DOM/DocumentLoading.cpp
+++ b/Userland/Libraries/LibWeb/DOM/DocumentLoading.cpp
@@ -126,7 +126,7 @@ static bool build_image_document(DOM::Document& document, ByteBuffer const& data
     MUST(html_element->append_child(body_element));
 
     auto image_element = DOM::create_element(document, HTML::TagNames::img, Namespace::HTML).release_value_but_fixme_should_propagate_errors();
-    MUST(image_element->set_attribute(HTML::AttributeNames::src, document.url().to_deprecated_string()));
+    MUST(image_element->set_attribute(HTML::AttributeNames::src, MUST(document.url().to_string())));
     MUST(body_element->append_child(image_element));
 
     return true;
@@ -170,9 +170,9 @@ static bool build_video_document(DOM::Document& document)
     MUST(html_element->append_child(body_element));
 
     auto video_element = DOM::create_element(document, HTML::TagNames::video, Namespace::HTML).release_value_but_fixme_should_propagate_errors();
-    MUST(video_element->set_attribute(HTML::AttributeNames::src, document.url().to_deprecated_string()));
-    MUST(video_element->set_attribute(HTML::AttributeNames::autoplay, DeprecatedString::empty()));
-    MUST(video_element->set_attribute(HTML::AttributeNames::controls, DeprecatedString::empty()));
+    MUST(video_element->set_attribute(HTML::AttributeNames::src, MUST(document.url().to_string())));
+    MUST(video_element->set_attribute(HTML::AttributeNames::autoplay, String {}));
+    MUST(video_element->set_attribute(HTML::AttributeNames::controls, String {}));
     MUST(body_element->append_child(video_element));
 
     return true;
@@ -190,9 +190,9 @@ static bool build_audio_document(DOM::Document& document)
     MUST(html_element->append_child(body_element));
 
     auto video_element = DOM::create_element(document, HTML::TagNames::audio, Namespace::HTML).release_value_but_fixme_should_propagate_errors();
-    MUST(video_element->set_attribute(HTML::AttributeNames::src, document.url().to_deprecated_string()));
-    MUST(video_element->set_attribute(HTML::AttributeNames::autoplay, DeprecatedString::empty()));
-    MUST(video_element->set_attribute(HTML::AttributeNames::controls, DeprecatedString::empty()));
+    MUST(video_element->set_attribute(HTML::AttributeNames::src, MUST(document.url().to_string())));
+    MUST(video_element->set_attribute(HTML::AttributeNames::autoplay, String {}));
+    MUST(video_element->set_attribute(HTML::AttributeNames::controls, String {}));
     MUST(body_element->append_child(video_element));
 
     return true;
diff --git a/Userland/Libraries/LibWeb/DOM/Element.cpp b/Userland/Libraries/LibWeb/DOM/Element.cpp
index 4eeb5f3127a..c145996c10a 100644
--- a/Userland/Libraries/LibWeb/DOM/Element.cpp
+++ b/Userland/Libraries/LibWeb/DOM/Element.cpp
@@ -468,7 +468,7 @@ void Element::add_attribute_change_steps(AttributeChangeSteps steps)
     m_attribute_change_steps.append(move(steps));
 }
 
-void Element::run_attribute_change_steps(DeprecatedFlyString const& local_name, DeprecatedString const& old_value, DeprecatedString const& value, DeprecatedFlyString const& namespace_)
+void Element::run_attribute_change_steps(FlyString const& local_name, DeprecatedString const& old_value, DeprecatedString const& value, DeprecatedFlyString const& namespace_)
 {
     for (auto const& attribute_change_steps : m_attribute_change_steps)
         attribute_change_steps(local_name, old_value, value, namespace_);
@@ -478,7 +478,7 @@ void Element::run_attribute_change_steps(DeprecatedFlyString const& local_name,
     invalidate_style_after_attribute_change(local_name);
 }
 
-void Element::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void Element::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     if (name == HTML::AttributeNames::class_) {
         auto new_classes = value.split_view(Infra::is_ascii_whitespace);
@@ -614,7 +614,7 @@ NonnullRefPtr<CSS::StyleProperties> Element::resolved_css_values()
 DOMTokenList* Element::class_list()
 {
     if (!m_class_list)
-        m_class_list = DOMTokenList::create(*this, FlyString::from_deprecated_fly_string(HTML::AttributeNames::class_).release_value());
+        m_class_list = DOMTokenList::create(*this, HTML::AttributeNames::class_);
     return m_class_list;
 }
 
@@ -1026,7 +1026,7 @@ i32 Element::tab_index() const
 // https://html.spec.whatwg.org/multipage/interaction.html#dom-tabindex
 void Element::set_tab_index(i32 tab_index)
 {
-    MUST(set_attribute(HTML::AttributeNames::tabindex, DeprecatedString::number(tab_index)));
+    MUST(set_attribute(HTML::AttributeNames::tabindex, MUST(String::number(tab_index))));
 }
 
 // https://drafts.csswg.org/cssom-view/#potentially-scrollable
@@ -1583,7 +1583,7 @@ ErrorOr<void> Element::scroll_into_view(Optional<Variant<bool, ScrollIntoViewOpt
     // FIXME: 8. Optionally perform some other action that brings the element to the user’s attention.
 }
 
-void Element::invalidate_style_after_attribute_change(DeprecatedFlyString const& attribute_name)
+void Element::invalidate_style_after_attribute_change(FlyString const& attribute_name)
 {
     // FIXME: Only invalidate if the attribute can actually affect style.
     (void)attribute_name;
@@ -1873,11 +1873,11 @@ void Element::set_prefix(Optional<FlyString> value)
     m_qualified_name.set_prefix(move(value));
 }
 
-void Element::for_each_attribute(Function<void(DeprecatedFlyString const&, DeprecatedString const&)> callback) const
+void Element::for_each_attribute(Function<void(FlyString const&, DeprecatedString const&)> callback) const
 {
     for (size_t i = 0; i < m_attributes->length(); ++i) {
         auto const* attribute = m_attributes->item(i);
-        callback(attribute->name().to_deprecated_fly_string(), attribute->value().to_deprecated_string());
+        callback(attribute->name(), attribute->value().to_deprecated_string());
     }
 }
 
diff --git a/Userland/Libraries/LibWeb/DOM/Element.h b/Userland/Libraries/LibWeb/DOM/Element.h
index fe7fad308ae..ba0e84cdbf5 100644
--- a/Userland/Libraries/LibWeb/DOM/Element.h
+++ b/Userland/Libraries/LibWeb/DOM/Element.h
@@ -145,7 +145,7 @@ public:
     int client_width() const;
     int client_height() const;
 
-    void for_each_attribute(Function<void(DeprecatedFlyString const&, DeprecatedString const&)>) const;
+    void for_each_attribute(Function<void(FlyString const&, DeprecatedString const&)>) const;
 
     bool has_class(FlyString const&, CaseSensitivity = CaseSensitivity::CaseSensitive) const;
     Vector<FlyString> const& class_names() const { return m_classes; }
@@ -153,11 +153,11 @@ public:
     virtual void apply_presentational_hints(CSS::StyleProperties&) const { }
 
     // https://dom.spec.whatwg.org/#concept-element-attributes-change-ext
-    using AttributeChangeSteps = Function<void(DeprecatedFlyString const& /*local_name*/, DeprecatedString const& /*old_value*/, DeprecatedString const& /*value*/, DeprecatedFlyString const& /*namespace_*/)>;
+    using AttributeChangeSteps = Function<void(FlyString const& /*local_name*/, DeprecatedString const& /*old_value*/, DeprecatedString const& /*value*/, DeprecatedFlyString const& /*namespace_*/)>;
 
     void add_attribute_change_steps(AttributeChangeSteps steps);
-    void run_attribute_change_steps(DeprecatedFlyString const& local_name, DeprecatedString const& old_value, DeprecatedString const& value, DeprecatedFlyString const& namespace_);
-    virtual void attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value);
+    void run_attribute_change_steps(FlyString const& local_name, DeprecatedString const& old_value, DeprecatedString const& value, DeprecatedFlyString const& namespace_);
+    virtual void attribute_changed(FlyString const& name, DeprecatedString const& value);
 
     struct [[nodiscard]] RequiredInvalidationAfterStyleChange {
         bool repaint { false };
@@ -386,7 +386,7 @@ protected:
 private:
     void make_html_uppercased_qualified_name();
 
-    void invalidate_style_after_attribute_change(DeprecatedFlyString const& attribute_name);
+    void invalidate_style_after_attribute_change(FlyString const& attribute_name);
 
     WebIDL::ExceptionOr<JS::GCPtr<Node>> insert_adjacent(DeprecatedString const& where, JS::NonnullGCPtr<Node> node);
 
diff --git a/Userland/Libraries/LibWeb/DOM/Node.cpp b/Userland/Libraries/LibWeb/DOM/Node.cpp
index 5692d729d2c..875eb60ac80 100644
--- a/Userland/Libraries/LibWeb/DOM/Node.cpp
+++ b/Userland/Libraries/LibWeb/DOM/Node.cpp
@@ -131,7 +131,7 @@ const HTML::HTMLElement* Node::enclosing_html_element() const
     return first_ancestor_of_type<HTML::HTMLElement>();
 }
 
-const HTML::HTMLElement* Node::enclosing_html_element_with_attribute(DeprecatedFlyString const& attribute) const
+const HTML::HTMLElement* Node::enclosing_html_element_with_attribute(FlyString const& attribute) const
 {
     for (auto* node = this; node; node = node->parent()) {
         if (is<HTML::HTMLElement>(*node) && verify_cast<HTML::HTMLElement>(*node).has_attribute(attribute))
@@ -815,7 +815,7 @@ JS::NonnullGCPtr<Node> Node::clone_node(Document* document, bool clone_children)
         element.for_each_attribute([&](auto& name, auto& value) {
             // 1. Let copyAttribute be a clone of attribute.
             // 2. Append copyAttribute to copy.
-            MUST(element_copy->set_attribute(name, value));
+            MUST(element_copy->set_attribute(name, MUST(String::from_deprecated_string(value))));
         });
         copy = move(element_copy);
 
diff --git a/Userland/Libraries/LibWeb/DOM/Node.h b/Userland/Libraries/LibWeb/DOM/Node.h
index f1be3851288..b2bd6bcea9e 100644
--- a/Userland/Libraries/LibWeb/DOM/Node.h
+++ b/Userland/Libraries/LibWeb/DOM/Node.h
@@ -158,7 +158,7 @@ public:
 
     const HTML::HTMLAnchorElement* enclosing_link_element() const;
     const HTML::HTMLElement* enclosing_html_element() const;
-    const HTML::HTMLElement* enclosing_html_element_with_attribute(DeprecatedFlyString const&) const;
+    const HTML::HTMLElement* enclosing_html_element_with_attribute(FlyString const&) const;
 
     DeprecatedString child_text_content() const;
 
diff --git a/Userland/Libraries/LibWeb/HTML/AttributeNames.cpp b/Userland/Libraries/LibWeb/HTML/AttributeNames.cpp
index 568e1334f60..935b6d3dbb8 100644
--- a/Userland/Libraries/LibWeb/HTML/AttributeNames.cpp
+++ b/Userland/Libraries/LibWeb/HTML/AttributeNames.cpp
@@ -9,7 +9,7 @@
 namespace Web::HTML {
 namespace AttributeNames {
 
-#define __ENUMERATE_HTML_ATTRIBUTE(name) DeprecatedFlyString name;
+#define __ENUMERATE_HTML_ATTRIBUTE(name) FlyString name;
 ENUMERATE_HTML_ATTRIBUTES
 #undef __ENUMERATE_HTML_ATTRIBUTE
 
@@ -19,19 +19,19 @@ void initialize_strings()
     VERIFY(!s_initialized);
 
 #define __ENUMERATE_HTML_ATTRIBUTE(name) \
-    name = #name;
+    name = #name##_fly_string;
     ENUMERATE_HTML_ATTRIBUTES
 #undef __ENUMERATE_HTML_ATTRIBUTE
 
     // NOTE: Special cases for C++ keywords.
-    class_ = "class";
-    for_ = "for";
-    default_ = "default";
-    char_ = "char";
+    class_ = "class"_fly_string;
+    for_ = "for"_fly_string;
+    default_ = "default"_fly_string;
+    char_ = "char"_fly_string;
 
     // NOTE: Special cases for attributes with dashes in them.
-    accept_charset = "accept-charset";
-    http_equiv = "http-equiv";
+    accept_charset = "accept-charset"_fly_string;
+    http_equiv = "http-equiv"_fly_string;
 
     s_initialized = true;
 }
@@ -39,7 +39,7 @@ void initialize_strings()
 }
 
 // https://html.spec.whatwg.org/#boolean-attribute
-bool is_boolean_attribute(DeprecatedFlyString const& attribute)
+bool is_boolean_attribute(FlyString const& attribute)
 {
     // NOTE: This is the list of attributes from https://html.spec.whatwg.org/#attributes-3
     //       with a Value column value of "Boolean attribute".
diff --git a/Userland/Libraries/LibWeb/HTML/AttributeNames.h b/Userland/Libraries/LibWeb/HTML/AttributeNames.h
index b037428f257..a8ec466eda7 100644
--- a/Userland/Libraries/LibWeb/HTML/AttributeNames.h
+++ b/Userland/Libraries/LibWeb/HTML/AttributeNames.h
@@ -6,8 +6,8 @@
 
 #pragma once
 
-#include <AK/DeprecatedFlyString.h>
 #include <AK/Error.h>
+#include <AK/FlyString.h>
 
 namespace Web::HTML {
 namespace AttributeNames {
@@ -240,7 +240,7 @@ namespace AttributeNames {
     __ENUMERATE_HTML_ATTRIBUTE(width)                      \
     __ENUMERATE_HTML_ATTRIBUTE(wrap)
 
-#define __ENUMERATE_HTML_ATTRIBUTE(name) extern DeprecatedFlyString name;
+#define __ENUMERATE_HTML_ATTRIBUTE(name) extern FlyString name;
 ENUMERATE_HTML_ATTRIBUTES
 #undef __ENUMERATE_HTML_ATTRIBUTE
 
@@ -248,6 +248,6 @@ void initialize_strings();
 
 }
 
-bool is_boolean_attribute(DeprecatedFlyString const& attribute);
+bool is_boolean_attribute(FlyString const& attribute);
 
 }
diff --git a/Userland/Libraries/LibWeb/HTML/DOMStringMap.cpp b/Userland/Libraries/LibWeb/HTML/DOMStringMap.cpp
index 9e1270c1d42..e452c31a192 100644
--- a/Userland/Libraries/LibWeb/HTML/DOMStringMap.cpp
+++ b/Userland/Libraries/LibWeb/HTML/DOMStringMap.cpp
@@ -48,10 +48,10 @@ Vector<DOMStringMap::NameValuePair> DOMStringMap::get_name_value_pairs() const
     //    in the order that those attributes are listed in the element's attribute list, add a name-value pair to list whose name is the attribute's name with the first five characters removed and whose value
     //    is the attribute's value.
     m_associated_element->for_each_attribute([&](auto& name, auto& value) {
-        if (!name.starts_with("data-"sv))
+        if (!name.bytes_as_string_view().starts_with("data-"sv))
             return;
 
-        auto name_after_starting_data = name.view().substring_view(5);
+        auto name_after_starting_data = name.bytes_as_string_view().substring_view(5);
 
         for (auto character : name_after_starting_data) {
             if (is_ascii_upper_alpha(character))
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLAnchorElement.cpp b/Userland/Libraries/LibWeb/HTML/HTMLAnchorElement.cpp
index f4bb1479b38..ba04654c1e0 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLAnchorElement.cpp
+++ b/Userland/Libraries/LibWeb/HTML/HTMLAnchorElement.cpp
@@ -27,7 +27,7 @@ void HTMLAnchorElement::initialize(JS::Realm& realm)
     set_prototype(&Bindings::ensure_web_prototype<Bindings::HTMLAnchorElementPrototype>(realm, "HTMLAnchorElement"));
 }
 
-void HTMLAnchorElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void HTMLAnchorElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     HTMLElement::attribute_changed(name, value);
     if (name == HTML::AttributeNames::href) {
@@ -40,7 +40,7 @@ DeprecatedString HTMLAnchorElement::hyperlink_element_utils_href() const
     return deprecated_attribute(HTML::AttributeNames::href);
 }
 
-WebIDL::ExceptionOr<void> HTMLAnchorElement::set_hyperlink_element_utils_href(DeprecatedString href)
+WebIDL::ExceptionOr<void> HTMLAnchorElement::set_hyperlink_element_utils_href(String href)
 {
     return set_attribute(HTML::AttributeNames::href, move(href));
 }
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLAnchorElement.h b/Userland/Libraries/LibWeb/HTML/HTMLAnchorElement.h
index bd27729a454..2573d9d5ca8 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLAnchorElement.h
+++ b/Userland/Libraries/LibWeb/HTML/HTMLAnchorElement.h
@@ -43,13 +43,13 @@ private:
     void run_activation_behavior(Web::DOM::Event const&);
 
     // ^DOM::Element
-    virtual void attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value) override;
+    virtual void attribute_changed(FlyString const& name, DeprecatedString const& value) override;
     virtual i32 default_tab_index_value() const override;
 
     // ^HTML::HTMLHyperlinkElementUtils
     virtual DOM::Document& hyperlink_element_utils_document() override { return document(); }
     virtual DeprecatedString hyperlink_element_utils_href() const override;
-    virtual WebIDL::ExceptionOr<void> set_hyperlink_element_utils_href(DeprecatedString) override;
+    virtual WebIDL::ExceptionOr<void> set_hyperlink_element_utils_href(String) override;
     virtual bool hyperlink_element_utils_is_html_anchor_element() const final { return true; }
     virtual bool hyperlink_element_utils_is_connected() const final { return is_connected(); }
     virtual void hyperlink_element_utils_queue_an_element_task(HTML::Task::Source source, Function<void()> steps) override
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLAreaElement.cpp b/Userland/Libraries/LibWeb/HTML/HTMLAreaElement.cpp
index 6da8b55e559..e871d979854 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLAreaElement.cpp
+++ b/Userland/Libraries/LibWeb/HTML/HTMLAreaElement.cpp
@@ -23,7 +23,7 @@ void HTMLAreaElement::initialize(JS::Realm& realm)
     set_prototype(&Bindings::ensure_web_prototype<Bindings::HTMLAreaElementPrototype>(realm, "HTMLAreaElement"));
 }
 
-void HTMLAreaElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void HTMLAreaElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     HTMLElement::attribute_changed(name, value);
     if (name == HTML::AttributeNames::href) {
@@ -36,7 +36,7 @@ DeprecatedString HTMLAreaElement::hyperlink_element_utils_href() const
     return deprecated_attribute(HTML::AttributeNames::href);
 }
 
-WebIDL::ExceptionOr<void> HTMLAreaElement::set_hyperlink_element_utils_href(DeprecatedString href)
+WebIDL::ExceptionOr<void> HTMLAreaElement::set_hyperlink_element_utils_href(String href)
 {
     return set_attribute(HTML::AttributeNames::href, move(href));
 }
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLAreaElement.h b/Userland/Libraries/LibWeb/HTML/HTMLAreaElement.h
index a70cd58991d..3c407c2d21b 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLAreaElement.h
+++ b/Userland/Libraries/LibWeb/HTML/HTMLAreaElement.h
@@ -26,13 +26,13 @@ private:
     virtual void initialize(JS::Realm&) override;
 
     // ^DOM::Element
-    virtual void attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value) override;
+    virtual void attribute_changed(FlyString const& name, DeprecatedString const& value) override;
     virtual i32 default_tab_index_value() const override;
 
     // ^HTML::HTMLHyperlinkElementUtils
     virtual DOM::Document& hyperlink_element_utils_document() override { return document(); }
     virtual DeprecatedString hyperlink_element_utils_href() const override;
-    virtual WebIDL::ExceptionOr<void> set_hyperlink_element_utils_href(DeprecatedString) override;
+    virtual WebIDL::ExceptionOr<void> set_hyperlink_element_utils_href(String) override;
     virtual bool hyperlink_element_utils_is_html_anchor_element() const override { return false; }
     virtual bool hyperlink_element_utils_is_connected() const override { return is_connected(); }
     virtual void hyperlink_element_utils_queue_an_element_task(HTML::Task::Source source, Function<void()> steps) override
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLBaseElement.cpp b/Userland/Libraries/LibWeb/HTML/HTMLBaseElement.cpp
index 0ad8e328761..9730235c4fd 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLBaseElement.cpp
+++ b/Userland/Libraries/LibWeb/HTML/HTMLBaseElement.cpp
@@ -43,7 +43,7 @@ void HTMLBaseElement::removed_from(Node* parent)
     document().update_base_element({});
 }
 
-void HTMLBaseElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void HTMLBaseElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     HTMLElement::attribute_changed(name, value);
 
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLBaseElement.h b/Userland/Libraries/LibWeb/HTML/HTMLBaseElement.h
index b1157847292..975bea911ef 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLBaseElement.h
+++ b/Userland/Libraries/LibWeb/HTML/HTMLBaseElement.h
@@ -23,7 +23,7 @@ public:
 
     virtual void inserted() override;
     virtual void removed_from(Node*) override;
-    virtual void attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value) override;
+    virtual void attribute_changed(FlyString const& name, DeprecatedString const& value) override;
 
 private:
     HTMLBaseElement(DOM::Document&, DOM::QualifiedName);
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLBodyElement.cpp b/Userland/Libraries/LibWeb/HTML/HTMLBodyElement.cpp
index d38af321d10..6460ca89b48 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLBodyElement.cpp
+++ b/Userland/Libraries/LibWeb/HTML/HTMLBodyElement.cpp
@@ -55,7 +55,7 @@ void HTMLBodyElement::apply_presentational_hints(CSS::StyleProperties& style) co
     });
 }
 
-void HTMLBodyElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void HTMLBodyElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     HTMLElement::attribute_changed(name, value);
     if (name.equals_ignoring_ascii_case("link"sv)) {
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLBodyElement.h b/Userland/Libraries/LibWeb/HTML/HTMLBodyElement.h
index ba96a216e3e..921aeff1bec 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLBodyElement.h
+++ b/Userland/Libraries/LibWeb/HTML/HTMLBodyElement.h
@@ -20,7 +20,7 @@ class HTMLBodyElement final
 public:
     virtual ~HTMLBodyElement() override;
 
-    virtual void attribute_changed(DeprecatedFlyString const&, DeprecatedString const&) override;
+    virtual void attribute_changed(FlyString const&, DeprecatedString const&) override;
     virtual void apply_presentational_hints(CSS::StyleProperties&) const override;
 
     // https://www.w3.org/TR/html-aria/#el-body
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLCanvasElement.cpp b/Userland/Libraries/LibWeb/HTML/HTMLCanvasElement.cpp
index 9ab610e96a4..de35643938f 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLCanvasElement.cpp
+++ b/Userland/Libraries/LibWeb/HTML/HTMLCanvasElement.cpp
@@ -111,7 +111,7 @@ void HTMLCanvasElement::reset_context_to_default_state()
 
 WebIDL::ExceptionOr<void> HTMLCanvasElement::set_width(unsigned value)
 {
-    TRY(set_attribute(HTML::AttributeNames::width, DeprecatedString::number(value)));
+    TRY(set_attribute(HTML::AttributeNames::width, MUST(String::number(value))));
     m_bitmap = nullptr;
     reset_context_to_default_state();
     return {};
@@ -119,7 +119,7 @@ WebIDL::ExceptionOr<void> HTMLCanvasElement::set_width(unsigned value)
 
 WebIDL::ExceptionOr<void> HTMLCanvasElement::set_height(unsigned value)
 {
-    TRY(set_attribute(HTML::AttributeNames::height, DeprecatedString::number(value)));
+    TRY(set_attribute(HTML::AttributeNames::height, MUST(String::number(value))));
     m_bitmap = nullptr;
     reset_context_to_default_state();
     return {};
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLDetailsElement.cpp b/Userland/Libraries/LibWeb/HTML/HTMLDetailsElement.cpp
index d17f3e2d51d..08fabf8f6ce 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLDetailsElement.cpp
+++ b/Userland/Libraries/LibWeb/HTML/HTMLDetailsElement.cpp
@@ -41,7 +41,7 @@ void HTMLDetailsElement::initialize(JS::Realm& realm)
     create_shadow_tree(realm).release_value_but_fixme_should_propagate_errors();
 }
 
-void HTMLDetailsElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void HTMLDetailsElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     Base::attribute_changed(name, value);
 
@@ -160,13 +160,13 @@ void HTMLDetailsElement::update_shadow_tree_style()
     if (has_attribute(HTML::AttributeNames::open)) {
         MUST(m_descendants_slot->set_attribute(HTML::AttributeNames::style, R"~~~(
             display: block;
-        )~~~"));
+        )~~~"_string));
     } else {
         // FIXME: Should be `display: block` but we do not support `content-visibility: hidden`.
         MUST(m_descendants_slot->set_attribute(HTML::AttributeNames::style, R"~~~(
             display: none;
             content-visibility: hidden;
-        )~~~"));
+        )~~~"_string));
     }
 }
 
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLDetailsElement.h b/Userland/Libraries/LibWeb/HTML/HTMLDetailsElement.h
index 47da32973f5..12c051c30cb 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLDetailsElement.h
+++ b/Userland/Libraries/LibWeb/HTML/HTMLDetailsElement.h
@@ -31,7 +31,7 @@ private:
     virtual void visit_edges(Cell::Visitor&) override;
 
     virtual void children_changed() override;
-    virtual void attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value) override;
+    virtual void attribute_changed(FlyString const& name, DeprecatedString const& value) override;
 
     void queue_a_details_toggle_event_task(String old_state, String new_state);
 
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLElement.cpp b/Userland/Libraries/LibWeb/HTML/HTMLElement.cpp
index 72390694a60..e3da52de824 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLElement.cpp
+++ b/Userland/Libraries/LibWeb/HTML/HTMLElement.cpp
@@ -112,11 +112,11 @@ WebIDL::ExceptionOr<void> HTMLElement::set_content_editable(StringView content_e
         return {};
     }
     if (content_editable.equals_ignoring_ascii_case("true"sv)) {
-        MUST(set_attribute(HTML::AttributeNames::contenteditable, "true"));
+        MUST(set_attribute(HTML::AttributeNames::contenteditable, "true"_string));
         return {};
     }
     if (content_editable.equals_ignoring_ascii_case("false"sv)) {
-        MUST(set_attribute(HTML::AttributeNames::contenteditable, "false"));
+        MUST(set_attribute(HTML::AttributeNames::contenteditable, "false"_string));
         return {};
     }
     return WebIDL::SyntaxError::create(realm(), "Invalid contentEditable value, must be 'true', 'false', or 'inherit'"_fly_string);
@@ -224,7 +224,7 @@ bool HTMLElement::cannot_navigate() const
     return !is<HTML::HTMLAnchorElement>(this) && !is_connected();
 }
 
-void HTMLElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void HTMLElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     Element::attribute_changed(name, value);
 
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLElement.h b/Userland/Libraries/LibWeb/HTML/HTMLElement.h
index 037eb0caeee..77dfddc4a37 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLElement.h
+++ b/Userland/Libraries/LibWeb/HTML/HTMLElement.h
@@ -70,7 +70,7 @@ protected:
 
     virtual void initialize(JS::Realm&) override;
 
-    virtual void attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value) override;
+    virtual void attribute_changed(FlyString const& name, DeprecatedString const& value) override;
 
     virtual void visit_edges(Cell::Visitor&) override;
 
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLFrameSetElement.cpp b/Userland/Libraries/LibWeb/HTML/HTMLFrameSetElement.cpp
index fb8bd4bf39a..a1c85dee786 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLFrameSetElement.cpp
+++ b/Userland/Libraries/LibWeb/HTML/HTMLFrameSetElement.cpp
@@ -23,7 +23,7 @@ void HTMLFrameSetElement::initialize(JS::Realm& realm)
     set_prototype(&Bindings::ensure_web_prototype<Bindings::HTMLFrameSetElementPrototype>(realm, "HTMLFrameSetElement"));
 }
 
-void HTMLFrameSetElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void HTMLFrameSetElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     HTMLElement::attribute_changed(name, value);
 
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLFrameSetElement.h b/Userland/Libraries/LibWeb/HTML/HTMLFrameSetElement.h
index 6489a1a681d..d19dade9576 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLFrameSetElement.h
+++ b/Userland/Libraries/LibWeb/HTML/HTMLFrameSetElement.h
@@ -24,7 +24,7 @@ private:
     HTMLFrameSetElement(DOM::Document&, DOM::QualifiedName);
 
     virtual void initialize(JS::Realm&) override;
-    virtual void attribute_changed(DeprecatedFlyString const&, DeprecatedString const&) override;
+    virtual void attribute_changed(FlyString const&, DeprecatedString const&) override;
 
     // ^HTML::GlobalEventHandlers
     virtual EventTarget& global_event_handlers_to_event_target(FlyString const& event_name) override;
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLHyperlinkElementUtils.cpp b/Userland/Libraries/LibWeb/HTML/HTMLHyperlinkElementUtils.cpp
index ffb16cc75e3..0e45f7c43a7 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLHyperlinkElementUtils.cpp
+++ b/Userland/Libraries/LibWeb/HTML/HTMLHyperlinkElementUtils.cpp
@@ -441,10 +441,10 @@ DeprecatedString HTMLHyperlinkElementUtils::href() const
 }
 
 // https://html.spec.whatwg.org/multipage/links.html#dom-hyperlink-href
-WebIDL::ExceptionOr<void> HTMLHyperlinkElementUtils::set_href(StringView href)
+WebIDL::ExceptionOr<void> HTMLHyperlinkElementUtils::set_href(String href)
 {
     // The href attribute's setter must set this element's href content attribute's value to the given value.
-    return set_hyperlink_element_utils_href(href);
+    return set_hyperlink_element_utils_href(move(href));
 }
 
 // https://html.spec.whatwg.org/multipage/links.html#update-href
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLHyperlinkElementUtils.h b/Userland/Libraries/LibWeb/HTML/HTMLHyperlinkElementUtils.h
index ec15a02d558..10c602e6bfc 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLHyperlinkElementUtils.h
+++ b/Userland/Libraries/LibWeb/HTML/HTMLHyperlinkElementUtils.h
@@ -20,7 +20,7 @@ public:
     DeprecatedString origin() const;
 
     DeprecatedString href() const;
-    WebIDL::ExceptionOr<void> set_href(StringView);
+    WebIDL::ExceptionOr<void> set_href(String);
 
     DeprecatedString protocol() const;
     void set_protocol(StringView);
@@ -52,7 +52,7 @@ public:
 protected:
     virtual DOM::Document& hyperlink_element_utils_document() = 0;
     virtual DeprecatedString hyperlink_element_utils_href() const = 0;
-    virtual WebIDL::ExceptionOr<void> set_hyperlink_element_utils_href(DeprecatedString) = 0;
+    virtual WebIDL::ExceptionOr<void> set_hyperlink_element_utils_href(String) = 0;
     virtual bool hyperlink_element_utils_is_html_anchor_element() const = 0;
     virtual bool hyperlink_element_utils_is_connected() const = 0;
     virtual DeprecatedString hyperlink_element_utils_get_an_elements_target() const = 0;
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLIFrameElement.cpp b/Userland/Libraries/LibWeb/HTML/HTMLIFrameElement.cpp
index 26305d5385a..516b350ca97 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLIFrameElement.cpp
+++ b/Userland/Libraries/LibWeb/HTML/HTMLIFrameElement.cpp
@@ -33,7 +33,7 @@ JS::GCPtr<Layout::Node> HTMLIFrameElement::create_layout_node(NonnullRefPtr<CSS:
     return heap().allocate_without_realm<Layout::FrameBox>(document(), *this, move(style));
 }
 
-void HTMLIFrameElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void HTMLIFrameElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     HTMLElement::attribute_changed(name, value);
     if (m_content_navigable)
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLIFrameElement.h b/Userland/Libraries/LibWeb/HTML/HTMLIFrameElement.h
index 994b7d9e41c..6039dd70112 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLIFrameElement.h
+++ b/Userland/Libraries/LibWeb/HTML/HTMLIFrameElement.h
@@ -36,7 +36,7 @@ private:
     // ^DOM::Element
     virtual void inserted() override;
     virtual void removed_from(Node*) override;
-    virtual void attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value) override;
+    virtual void attribute_changed(FlyString const& name, DeprecatedString const& value) override;
     virtual i32 default_tab_index_value() const override;
 
     // https://html.spec.whatwg.org/multipage/iframe-embed-object.html#process-the-iframe-attributes
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLImageElement.cpp b/Userland/Libraries/LibWeb/HTML/HTMLImageElement.cpp
index ddb0ac8d90b..a3beb65306f 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLImageElement.cpp
+++ b/Userland/Libraries/LibWeb/HTML/HTMLImageElement.cpp
@@ -95,7 +95,7 @@ void HTMLImageElement::apply_presentational_hints(CSS::StyleProperties& style) c
     });
 }
 
-void HTMLImageElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void HTMLImageElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     HTMLElement::attribute_changed(name, value);
 
@@ -190,7 +190,7 @@ unsigned HTMLImageElement::width() const
 
 WebIDL::ExceptionOr<void> HTMLImageElement::set_width(unsigned width)
 {
-    return set_attribute(HTML::AttributeNames::width, DeprecatedString::number(width));
+    return set_attribute(HTML::AttributeNames::width, MUST(String::number(width)));
 }
 
 // https://html.spec.whatwg.org/multipage/embedded-content.html#dom-img-height
@@ -218,7 +218,7 @@ unsigned HTMLImageElement::height() const
 
 WebIDL::ExceptionOr<void> HTMLImageElement::set_height(unsigned height)
 {
-    return set_attribute(HTML::AttributeNames::height, DeprecatedString::number(height));
+    return set_attribute(HTML::AttributeNames::height, MUST(String::number(height)));
 }
 
 // https://html.spec.whatwg.org/multipage/embedded-content.html#dom-img-naturalwidth
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLImageElement.h b/Userland/Libraries/LibWeb/HTML/HTMLImageElement.h
index 5e6710f0b85..5bab4f6a978 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLImageElement.h
+++ b/Userland/Libraries/LibWeb/HTML/HTMLImageElement.h
@@ -32,7 +32,7 @@ class HTMLImageElement final
 public:
     virtual ~HTMLImageElement() override;
 
-    virtual void attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value) override;
+    virtual void attribute_changed(FlyString const& name, DeprecatedString const& value) override;
 
     DeprecatedString alt() const { return deprecated_attribute(HTML::AttributeNames::alt); }
     DeprecatedString src() const { return deprecated_attribute(HTML::AttributeNames::src); }
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLInputElement.cpp b/Userland/Libraries/LibWeb/HTML/HTMLInputElement.cpp
index 27c226b79ad..7c5ae269ed6 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLInputElement.cpp
+++ b/Userland/Libraries/LibWeb/HTML/HTMLInputElement.cpp
@@ -532,7 +532,7 @@ void HTMLInputElement::create_shadow_tree_if_needed()
         white-space: pre;
         border: none;
         padding: 1px 2px;
-)~~~"));
+)~~~"_string));
 
     m_placeholder_element = heap().allocate<PlaceholderElement>(realm(), document());
     MUST(m_placeholder_element->style_for_bindings()->set_property(CSS::PropertyID::Height, "1lh"sv));
@@ -586,7 +586,7 @@ void HTMLInputElement::did_lose_focus()
     });
 }
 
-void HTMLInputElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void HTMLInputElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     HTMLElement::attribute_changed(name, value);
     if (name == HTML::AttributeNames::checked) {
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLInputElement.h b/Userland/Libraries/LibWeb/HTML/HTMLInputElement.h
index e9fbe5182a4..7afb67506e8 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLInputElement.h
+++ b/Userland/Libraries/LibWeb/HTML/HTMLInputElement.h
@@ -111,7 +111,7 @@ public:
     virtual bool is_focusable() const override { return m_type != TypeAttributeState::Hidden; }
 
     // ^HTMLElement
-    virtual void attribute_changed(DeprecatedFlyString const&, DeprecatedString const&) override;
+    virtual void attribute_changed(FlyString const&, DeprecatedString const&) override;
 
     // ^FormAssociatedElement
     // https://html.spec.whatwg.org/multipage/forms.html#category-listed
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLLinkElement.cpp b/Userland/Libraries/LibWeb/HTML/HTMLLinkElement.cpp
index 697f9507c3a..9ea9ee425b1 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLLinkElement.cpp
+++ b/Userland/Libraries/LibWeb/HTML/HTMLLinkElement.cpp
@@ -77,7 +77,7 @@ bool HTMLLinkElement::has_loaded_icon() const
     return m_relationship & Relationship::Icon && resource() && resource()->is_loaded() && resource()->has_encoded_data();
 }
 
-void HTMLLinkElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void HTMLLinkElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     HTMLElement::attribute_changed(name, value);
 
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLLinkElement.h b/Userland/Libraries/LibWeb/HTML/HTMLLinkElement.h
index 6e7f1602e35..4d0bfa32bc4 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLLinkElement.h
+++ b/Userland/Libraries/LibWeb/HTML/HTMLLinkElement.h
@@ -39,7 +39,7 @@ private:
     HTMLLinkElement(DOM::Document&, DOM::QualifiedName);
 
     virtual void initialize(JS::Realm&) override;
-    void attribute_changed(DeprecatedFlyString const&, DeprecatedString const&) override;
+    void attribute_changed(FlyString const&, DeprecatedString const&) override;
 
     // ^ResourceClient
     virtual void resource_did_fail() override;
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLMediaElement.cpp b/Userland/Libraries/LibWeb/HTML/HTMLMediaElement.cpp
index 90d14e372f1..99311e276c3 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLMediaElement.cpp
+++ b/Userland/Libraries/LibWeb/HTML/HTMLMediaElement.cpp
@@ -83,7 +83,7 @@ void HTMLMediaElement::visit_edges(Cell::Visitor& visitor)
     visitor.visit(m_fetch_controller);
 }
 
-void HTMLMediaElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void HTMLMediaElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     Base::attribute_changed(name, value);
 
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLMediaElement.h b/Userland/Libraries/LibWeb/HTML/HTMLMediaElement.h
index 9f064624fa7..b3fd2797124 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLMediaElement.h
+++ b/Userland/Libraries/LibWeb/HTML/HTMLMediaElement.h
@@ -134,7 +134,7 @@ protected:
     virtual void initialize(JS::Realm&) override;
     virtual void visit_edges(Cell::Visitor&) override;
 
-    virtual void attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value) override;
+    virtual void attribute_changed(FlyString const& name, DeprecatedString const& value) override;
     virtual void removed_from(DOM::Node*) override;
     virtual void children_changed() override;
 
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLObjectElement.cpp b/Userland/Libraries/LibWeb/HTML/HTMLObjectElement.cpp
index 3af2faa76b6..ad3e73c6027 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLObjectElement.cpp
+++ b/Userland/Libraries/LibWeb/HTML/HTMLObjectElement.cpp
@@ -45,7 +45,7 @@ void HTMLObjectElement::visit_edges(Cell::Visitor& visitor)
     visitor.visit(m_image_request);
 }
 
-void HTMLObjectElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void HTMLObjectElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     NavigableContainer::attribute_changed(name, value);
 
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLObjectElement.h b/Userland/Libraries/LibWeb/HTML/HTMLObjectElement.h
index be1ced8c390..8d7c0e27682 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLObjectElement.h
+++ b/Userland/Libraries/LibWeb/HTML/HTMLObjectElement.h
@@ -34,7 +34,7 @@ class HTMLObjectElement final
 public:
     virtual ~HTMLObjectElement() override;
 
-    virtual void attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value) override;
+    virtual void attribute_changed(FlyString const& name, DeprecatedString const& value) override;
 
     String data() const;
     void set_data(String const& data) { MUST(set_attribute(HTML::AttributeNames::data, data)); }
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLOptionElement.cpp b/Userland/Libraries/LibWeb/HTML/HTMLOptionElement.cpp
index aee6c046eb9..b928d9604f2 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLOptionElement.cpp
+++ b/Userland/Libraries/LibWeb/HTML/HTMLOptionElement.cpp
@@ -31,7 +31,7 @@ void HTMLOptionElement::initialize(JS::Realm& realm)
     set_prototype(&Bindings::ensure_web_prototype<Bindings::HTMLOptionElementPrototype>(realm, "HTMLOptionElement"));
 }
 
-void HTMLOptionElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void HTMLOptionElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     HTMLElement::attribute_changed(name, value);
 
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLOptionElement.h b/Userland/Libraries/LibWeb/HTML/HTMLOptionElement.h
index f8bc35d0881..4cda4810b2e 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLOptionElement.h
+++ b/Userland/Libraries/LibWeb/HTML/HTMLOptionElement.h
@@ -40,7 +40,7 @@ private:
 
     virtual void initialize(JS::Realm&) override;
 
-    void attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value) override;
+    void attribute_changed(FlyString const& name, DeprecatedString const& value) override;
 
     void ask_for_a_reset();
 
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLProgressElement.cpp b/Userland/Libraries/LibWeb/HTML/HTMLProgressElement.cpp
index 7e200789578..e1164f5e0aa 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLProgressElement.cpp
+++ b/Userland/Libraries/LibWeb/HTML/HTMLProgressElement.cpp
@@ -71,7 +71,7 @@ WebIDL::ExceptionOr<void> HTMLProgressElement::set_value(double value)
     if (value < 0)
         return {};
 
-    TRY(set_attribute(HTML::AttributeNames::value, DeprecatedString::number(value)));
+    TRY(set_attribute(HTML::AttributeNames::value, MUST(String::number(value))));
     progress_position_updated();
     return {};
 }
@@ -98,7 +98,7 @@ WebIDL::ExceptionOr<void> HTMLProgressElement::set_max(double value)
     if (value <= 0)
         return {};
 
-    TRY(set_attribute(HTML::AttributeNames::max, DeprecatedString::number(value)));
+    TRY(set_attribute(HTML::AttributeNames::max, MUST(String::number(value))));
     progress_position_updated();
     return {};
 }
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLScriptElement.cpp b/Userland/Libraries/LibWeb/HTML/HTMLScriptElement.cpp
index 0c7d99bd9d5..f2a7dd0d7f2 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLScriptElement.cpp
+++ b/Userland/Libraries/LibWeb/HTML/HTMLScriptElement.cpp
@@ -45,7 +45,7 @@ void HTMLScriptElement::visit_edges(Cell::Visitor& visitor)
     visitor.visit(m_preparation_time_document.ptr());
 }
 
-void HTMLScriptElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void HTMLScriptElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     Base::attribute_changed(name, value);
 
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLScriptElement.h b/Userland/Libraries/LibWeb/HTML/HTMLScriptElement.h
index f693c03cb97..506c00d467f 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLScriptElement.h
+++ b/Userland/Libraries/LibWeb/HTML/HTMLScriptElement.h
@@ -62,7 +62,7 @@ private:
     virtual void initialize(JS::Realm&) override;
     virtual void visit_edges(Cell::Visitor&) override;
 
-    virtual void attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value) override;
+    virtual void attribute_changed(FlyString const& name, DeprecatedString const& value) override;
 
     // https://html.spec.whatwg.org/multipage/scripting.html#prepare-the-script-element
     void prepare_script();
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLSummaryElement.cpp b/Userland/Libraries/LibWeb/HTML/HTMLSummaryElement.cpp
index 2b8d0c69203..f0d0b710e9e 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLSummaryElement.cpp
+++ b/Userland/Libraries/LibWeb/HTML/HTMLSummaryElement.cpp
@@ -27,7 +27,7 @@ HTMLSummaryElement::HTMLSummaryElement(DOM::Document& document, DOM::QualifiedNa
         if (parent->has_attribute(HTML::AttributeNames::open))
             parent->remove_attribute(HTML::AttributeNames::open);
         else
-            parent->set_attribute(HTML::AttributeNames::open, "").release_value_but_fixme_should_propagate_errors();
+            parent->set_attribute(HTML::AttributeNames::open, String {}).release_value_but_fixme_should_propagate_errors();
     };
 }
 
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLTableCellElement.cpp b/Userland/Libraries/LibWeb/HTML/HTMLTableCellElement.cpp
index 0fb700cb5fe..9c7f8d6e412 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLTableCellElement.cpp
+++ b/Userland/Libraries/LibWeb/HTML/HTMLTableCellElement.cpp
@@ -116,7 +116,7 @@ unsigned int HTMLTableCellElement::col_span() const
 
 WebIDL::ExceptionOr<void> HTMLTableCellElement::set_col_span(unsigned int value)
 {
-    return set_attribute(HTML::AttributeNames::colspan, DeprecatedString::number(value));
+    return set_attribute(HTML::AttributeNames::colspan, MUST(String::number(value)));
 }
 
 // This implements step 9 in the spec here:
@@ -136,7 +136,7 @@ unsigned int HTMLTableCellElement::row_span() const
 
 WebIDL::ExceptionOr<void> HTMLTableCellElement::set_row_span(unsigned int value)
 {
-    return set_attribute(HTML::AttributeNames::rowspan, DeprecatedString::number(value));
+    return set_attribute(HTML::AttributeNames::rowspan, MUST(String::number(value)));
 }
 
 Optional<ARIA::Role> HTMLTableCellElement::default_role() const
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLVideoElement.cpp b/Userland/Libraries/LibWeb/HTML/HTMLVideoElement.cpp
index 6d30e1ac2b1..e74db69cf1d 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLVideoElement.cpp
+++ b/Userland/Libraries/LibWeb/HTML/HTMLVideoElement.cpp
@@ -40,7 +40,7 @@ void HTMLVideoElement::visit_edges(Cell::Visitor& visitor)
     visitor.visit(m_fetch_controller);
 }
 
-void HTMLVideoElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void HTMLVideoElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     Base::attribute_changed(name, value);
 
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLVideoElement.h b/Userland/Libraries/LibWeb/HTML/HTMLVideoElement.h
index 3fdf5e76dd8..de2dae0233d 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLVideoElement.h
+++ b/Userland/Libraries/LibWeb/HTML/HTMLVideoElement.h
@@ -47,7 +47,7 @@ private:
     virtual void initialize(JS::Realm&) override;
     virtual void visit_edges(Cell::Visitor&) override;
 
-    virtual void attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value) override;
+    virtual void attribute_changed(FlyString const& name, DeprecatedString const& value) override;
 
     virtual JS::GCPtr<Layout::Node> create_layout_node(NonnullRefPtr<CSS::StyleProperties>) override;
 
diff --git a/Userland/Libraries/LibWeb/HTML/Parser/HTMLToken.h b/Userland/Libraries/LibWeb/HTML/Parser/HTMLToken.h
index 2a90b8fbd0f..d3110132696 100644
--- a/Userland/Libraries/LibWeb/HTML/Parser/HTMLToken.h
+++ b/Userland/Libraries/LibWeb/HTML/Parser/HTMLToken.h
@@ -247,28 +247,29 @@ public:
         }
     }
 
-    StringView attribute(DeprecatedFlyString const& attribute_name) const
+    StringView attribute(FlyString const& attribute_name) const
     {
         if (auto result = raw_attribute(attribute_name); result.has_value())
             return result->value;
         return {};
     }
 
-    Optional<Attribute const&> raw_attribute(DeprecatedFlyString const& attribute_name) const
+    Optional<Attribute const&> raw_attribute(FlyString const& attribute_name) const
     {
         VERIFY(is_start_tag() || is_end_tag());
 
+        auto deprecated_attribute_name = attribute_name.to_deprecated_fly_string();
         auto* ptr = tag_attributes();
         if (!ptr)
             return {};
         for (auto& attribute : *ptr) {
-            if (attribute_name == attribute.local_name)
+            if (deprecated_attribute_name == attribute.local_name)
                 return attribute;
         }
         return {};
     }
 
-    bool has_attribute(DeprecatedFlyString const& attribute_name)
+    bool has_attribute(FlyString const& attribute_name) const
     {
         return !attribute(attribute_name).is_null();
     }
diff --git a/Userland/Libraries/LibWeb/SVG/AttributeNames.cpp b/Userland/Libraries/LibWeb/SVG/AttributeNames.cpp
index 38689da2e12..d98c6a96e69 100644
--- a/Userland/Libraries/LibWeb/SVG/AttributeNames.cpp
+++ b/Userland/Libraries/LibWeb/SVG/AttributeNames.cpp
@@ -8,7 +8,7 @@
 
 namespace Web::SVG::AttributeNames {
 
-#define __ENUMERATE_SVG_ATTRIBUTE(name) DeprecatedFlyString name;
+#define __ENUMERATE_SVG_ATTRIBUTE(name) FlyString name;
 ENUMERATE_SVG_ATTRIBUTES(__ENUMERATE_SVG_ATTRIBUTE)
 #undef __ENUMERATE_SVG_ATTRIBUTE
 
@@ -18,7 +18,7 @@ void initialize_strings()
     VERIFY(!s_initialized);
 
 #define __ENUMERATE_SVG_ATTRIBUTE(name) \
-    name = #name;
+    name = #name##_fly_string;
     ENUMERATE_SVG_ATTRIBUTES(__ENUMERATE_SVG_ATTRIBUTE)
 #undef __ENUMERATE_SVG_ATTRIBUTE
 
diff --git a/Userland/Libraries/LibWeb/SVG/AttributeNames.h b/Userland/Libraries/LibWeb/SVG/AttributeNames.h
index 8dedb4ecc92..71f4f011a7f 100644
--- a/Userland/Libraries/LibWeb/SVG/AttributeNames.h
+++ b/Userland/Libraries/LibWeb/SVG/AttributeNames.h
@@ -6,8 +6,8 @@
 
 #pragma once
 
-#include <AK/DeprecatedFlyString.h>
 #include <AK/Error.h>
+#include <AK/FlyString.h>
 
 namespace Web::SVG::AttributeNames {
 
@@ -96,7 +96,7 @@ namespace Web::SVG::AttributeNames {
     E(yChannelSelector)             \
     E(zoomAndPan)
 
-#define __ENUMERATE_SVG_ATTRIBUTE(name) extern DeprecatedFlyString name;
+#define __ENUMERATE_SVG_ATTRIBUTE(name) extern FlyString name;
 ENUMERATE_SVG_ATTRIBUTES(__ENUMERATE_SVG_ATTRIBUTE)
 #undef __ENUMERATE_SVG_ATTRIBUTE
 
diff --git a/Userland/Libraries/LibWeb/SVG/SVGCircleElement.cpp b/Userland/Libraries/LibWeb/SVG/SVGCircleElement.cpp
index b5786256962..f481b262b1a 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGCircleElement.cpp
+++ b/Userland/Libraries/LibWeb/SVG/SVGCircleElement.cpp
@@ -22,7 +22,7 @@ void SVGCircleElement::initialize(JS::Realm& realm)
     set_prototype(&Bindings::ensure_web_prototype<Bindings::SVGCircleElementPrototype>(realm, "SVGCircleElement"));
 }
 
-void SVGCircleElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void SVGCircleElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     SVGGeometryElement::attribute_changed(name, value);
 
diff --git a/Userland/Libraries/LibWeb/SVG/SVGCircleElement.h b/Userland/Libraries/LibWeb/SVG/SVGCircleElement.h
index c24512c9f27..9471d5cb2a6 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGCircleElement.h
+++ b/Userland/Libraries/LibWeb/SVG/SVGCircleElement.h
@@ -17,7 +17,7 @@ class SVGCircleElement final : public SVGGeometryElement {
 public:
     virtual ~SVGCircleElement() override = default;
 
-    virtual void attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value) override;
+    virtual void attribute_changed(FlyString const& name, DeprecatedString const& value) override;
 
     virtual Gfx::Path& get_path() override;
 
diff --git a/Userland/Libraries/LibWeb/SVG/SVGElement.cpp b/Userland/Libraries/LibWeb/SVG/SVGElement.cpp
index e04301bd4c1..e8c63790749 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGElement.cpp
+++ b/Userland/Libraries/LibWeb/SVG/SVGElement.cpp
@@ -34,7 +34,7 @@ void SVGElement::visit_edges(Cell::Visitor& visitor)
     visitor.visit(m_dataset);
 }
 
-void SVGElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void SVGElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     Base::attribute_changed(name, value);
 
diff --git a/Userland/Libraries/LibWeb/SVG/SVGElement.h b/Userland/Libraries/LibWeb/SVG/SVGElement.h
index a31e7732a64..91df1fa65a1 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGElement.h
+++ b/Userland/Libraries/LibWeb/SVG/SVGElement.h
@@ -17,7 +17,7 @@ class SVGElement : public DOM::Element {
 public:
     virtual bool requires_svg_container() const override { return true; }
 
-    virtual void attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value) override;
+    virtual void attribute_changed(FlyString const& name, DeprecatedString const& value) override;
 
     virtual void children_changed() override;
     virtual void inserted() override;
diff --git a/Userland/Libraries/LibWeb/SVG/SVGEllipseElement.cpp b/Userland/Libraries/LibWeb/SVG/SVGEllipseElement.cpp
index fb8c1b3b55b..01498a14ab9 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGEllipseElement.cpp
+++ b/Userland/Libraries/LibWeb/SVG/SVGEllipseElement.cpp
@@ -22,7 +22,7 @@ void SVGEllipseElement::initialize(JS::Realm& realm)
     set_prototype(&Bindings::ensure_web_prototype<Bindings::SVGEllipseElementPrototype>(realm, "SVGEllipseElement"));
 }
 
-void SVGEllipseElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void SVGEllipseElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     SVGGeometryElement::attribute_changed(name, value);
 
diff --git a/Userland/Libraries/LibWeb/SVG/SVGEllipseElement.h b/Userland/Libraries/LibWeb/SVG/SVGEllipseElement.h
index ca538609852..bd88df19de0 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGEllipseElement.h
+++ b/Userland/Libraries/LibWeb/SVG/SVGEllipseElement.h
@@ -17,7 +17,7 @@ class SVGEllipseElement final : public SVGGeometryElement {
 public:
     virtual ~SVGEllipseElement() override = default;
 
-    virtual void attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value) override;
+    virtual void attribute_changed(FlyString const& name, DeprecatedString const& value) override;
 
     virtual Gfx::Path& get_path() override;
 
diff --git a/Userland/Libraries/LibWeb/SVG/SVGGradientElement.cpp b/Userland/Libraries/LibWeb/SVG/SVGGradientElement.cpp
index 265216f77b4..63a2d867863 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGGradientElement.cpp
+++ b/Userland/Libraries/LibWeb/SVG/SVGGradientElement.cpp
@@ -17,7 +17,7 @@ SVGGradientElement::SVGGradientElement(DOM::Document& document, DOM::QualifiedNa
 {
 }
 
-void SVGGradientElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void SVGGradientElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     SVGElement::attribute_changed(name, value);
     if (name == AttributeNames::gradientUnits) {
diff --git a/Userland/Libraries/LibWeb/SVG/SVGGradientElement.h b/Userland/Libraries/LibWeb/SVG/SVGGradientElement.h
index b4feb74b8bc..be6521083e0 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGGradientElement.h
+++ b/Userland/Libraries/LibWeb/SVG/SVGGradientElement.h
@@ -40,7 +40,7 @@ class SVGGradientElement : public SVGElement {
 public:
     virtual ~SVGGradientElement() override = default;
 
-    virtual void attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value) override;
+    virtual void attribute_changed(FlyString const& name, DeprecatedString const& value) override;
 
     virtual Optional<Gfx::PaintStyle const&> to_gfx_paint_style(SVGPaintContext const&) const = 0;
 
diff --git a/Userland/Libraries/LibWeb/SVG/SVGGraphicsElement.cpp b/Userland/Libraries/LibWeb/SVG/SVGGraphicsElement.cpp
index bc34f26b045..91e619ef95e 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGGraphicsElement.cpp
+++ b/Userland/Libraries/LibWeb/SVG/SVGGraphicsElement.cpp
@@ -32,7 +32,7 @@ void SVGGraphicsElement::initialize(JS::Realm& realm)
     set_prototype(&Bindings::ensure_web_prototype<Bindings::SVGGraphicsElementPrototype>(realm, "SVGGraphicsElement"));
 }
 
-void SVGGraphicsElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void SVGGraphicsElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     SVGElement::attribute_changed(name, value);
     if (name == "transform"sv) {
diff --git a/Userland/Libraries/LibWeb/SVG/SVGGraphicsElement.h b/Userland/Libraries/LibWeb/SVG/SVGGraphicsElement.h
index 806452a79d8..0b9c7cc7f41 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGGraphicsElement.h
+++ b/Userland/Libraries/LibWeb/SVG/SVGGraphicsElement.h
@@ -25,7 +25,7 @@ class SVGGraphicsElement : public SVGElement {
 public:
     virtual void apply_presentational_hints(CSS::StyleProperties&) const override;
 
-    virtual void attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value) override;
+    virtual void attribute_changed(FlyString const& name, DeprecatedString const& value) override;
 
     Optional<Gfx::Color> fill_color() const;
     Optional<FillRule> fill_rule() const;
diff --git a/Userland/Libraries/LibWeb/SVG/SVGLineElement.cpp b/Userland/Libraries/LibWeb/SVG/SVGLineElement.cpp
index 02514028294..7d341309eca 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGLineElement.cpp
+++ b/Userland/Libraries/LibWeb/SVG/SVGLineElement.cpp
@@ -22,7 +22,7 @@ void SVGLineElement::initialize(JS::Realm& realm)
     set_prototype(&Bindings::ensure_web_prototype<Bindings::SVGLineElementPrototype>(realm, "SVGLineElement"));
 }
 
-void SVGLineElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void SVGLineElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     SVGGeometryElement::attribute_changed(name, value);
 
diff --git a/Userland/Libraries/LibWeb/SVG/SVGLineElement.h b/Userland/Libraries/LibWeb/SVG/SVGLineElement.h
index 993395307f5..88a110622a6 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGLineElement.h
+++ b/Userland/Libraries/LibWeb/SVG/SVGLineElement.h
@@ -17,7 +17,7 @@ class SVGLineElement final : public SVGGeometryElement {
 public:
     virtual ~SVGLineElement() override = default;
 
-    virtual void attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value) override;
+    virtual void attribute_changed(FlyString const& name, DeprecatedString const& value) override;
 
     virtual Gfx::Path& get_path() override;
 
diff --git a/Userland/Libraries/LibWeb/SVG/SVGLinearGradientElement.cpp b/Userland/Libraries/LibWeb/SVG/SVGLinearGradientElement.cpp
index de2bee93ca9..b094c6adf14 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGLinearGradientElement.cpp
+++ b/Userland/Libraries/LibWeb/SVG/SVGLinearGradientElement.cpp
@@ -24,7 +24,7 @@ void SVGLinearGradientElement::initialize(JS::Realm& realm)
     set_prototype(&Bindings::ensure_web_prototype<Bindings::SVGLinearGradientElementPrototype>(realm, "SVGLinearGradientElement"));
 }
 
-void SVGLinearGradientElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void SVGLinearGradientElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     SVGGradientElement::attribute_changed(name, value);
 
diff --git a/Userland/Libraries/LibWeb/SVG/SVGLinearGradientElement.h b/Userland/Libraries/LibWeb/SVG/SVGLinearGradientElement.h
index a445fdc0e65..3153e9e138e 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGLinearGradientElement.h
+++ b/Userland/Libraries/LibWeb/SVG/SVGLinearGradientElement.h
@@ -18,7 +18,7 @@ class SVGLinearGradientElement : public SVGGradientElement {
 public:
     virtual ~SVGLinearGradientElement() override = default;
 
-    virtual void attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value) override;
+    virtual void attribute_changed(FlyString const& name, DeprecatedString const& value) override;
 
     virtual Optional<Gfx::PaintStyle const&> to_gfx_paint_style(SVGPaintContext const&) const override;
 
diff --git a/Userland/Libraries/LibWeb/SVG/SVGMaskElement.cpp b/Userland/Libraries/LibWeb/SVG/SVGMaskElement.cpp
index b113e1a0113..d27d5b5b362 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGMaskElement.cpp
+++ b/Userland/Libraries/LibWeb/SVG/SVGMaskElement.cpp
@@ -31,7 +31,7 @@ JS::GCPtr<Layout::Node> SVGMaskElement::create_layout_node(NonnullRefPtr<CSS::St
     return heap().allocate_without_realm<Layout::SVGGraphicsBox>(document(), *this, move(style));
 }
 
-void SVGMaskElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void SVGMaskElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     SVGGraphicsElement::attribute_changed(name, value);
     if (name == AttributeNames::maskUnits) {
diff --git a/Userland/Libraries/LibWeb/SVG/SVGMaskElement.h b/Userland/Libraries/LibWeb/SVG/SVGMaskElement.h
index 031284bf2e7..6f343edbe84 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGMaskElement.h
+++ b/Userland/Libraries/LibWeb/SVG/SVGMaskElement.h
@@ -17,7 +17,7 @@ class SVGMaskElement final : public SVGGraphicsElement {
 public:
     virtual ~SVGMaskElement() override;
 
-    virtual void attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value) override;
+    virtual void attribute_changed(FlyString const& name, DeprecatedString const& value) override;
 
     virtual JS::GCPtr<Layout::Node> create_layout_node(NonnullRefPtr<CSS::StyleProperties>) override;
 
diff --git a/Userland/Libraries/LibWeb/SVG/SVGPathElement.cpp b/Userland/Libraries/LibWeb/SVG/SVGPathElement.cpp
index e5a3ab17adf..3bbf0a531b7 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGPathElement.cpp
+++ b/Userland/Libraries/LibWeb/SVG/SVGPathElement.cpp
@@ -95,7 +95,7 @@ void SVGPathElement::initialize(JS::Realm& realm)
     set_prototype(&Bindings::ensure_web_prototype<Bindings::SVGPathElementPrototype>(realm, "SVGPathElement"));
 }
 
-void SVGPathElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void SVGPathElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     SVGGeometryElement::attribute_changed(name, value);
 
diff --git a/Userland/Libraries/LibWeb/SVG/SVGPathElement.h b/Userland/Libraries/LibWeb/SVG/SVGPathElement.h
index bec1ef94a21..fa37e627bf7 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGPathElement.h
+++ b/Userland/Libraries/LibWeb/SVG/SVGPathElement.h
@@ -19,7 +19,7 @@ class SVGPathElement final : public SVGGeometryElement {
 public:
     virtual ~SVGPathElement() override = default;
 
-    virtual void attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value) override;
+    virtual void attribute_changed(FlyString const& name, DeprecatedString const& value) override;
 
     virtual Gfx::Path& get_path() override;
 
diff --git a/Userland/Libraries/LibWeb/SVG/SVGPolygonElement.cpp b/Userland/Libraries/LibWeb/SVG/SVGPolygonElement.cpp
index 4fa87df75f3..42fd9955088 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGPolygonElement.cpp
+++ b/Userland/Libraries/LibWeb/SVG/SVGPolygonElement.cpp
@@ -22,7 +22,7 @@ void SVGPolygonElement::initialize(JS::Realm& realm)
     set_prototype(&Bindings::ensure_web_prototype<Bindings::SVGPolygonElementPrototype>(realm, "SVGPolygonElement"));
 }
 
-void SVGPolygonElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void SVGPolygonElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     SVGGeometryElement::attribute_changed(name, value);
 
diff --git a/Userland/Libraries/LibWeb/SVG/SVGPolygonElement.h b/Userland/Libraries/LibWeb/SVG/SVGPolygonElement.h
index 61ddb522b78..55457a6feb3 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGPolygonElement.h
+++ b/Userland/Libraries/LibWeb/SVG/SVGPolygonElement.h
@@ -16,7 +16,7 @@ class SVGPolygonElement final : public SVGGeometryElement {
 public:
     virtual ~SVGPolygonElement() override = default;
 
-    virtual void attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value) override;
+    virtual void attribute_changed(FlyString const& name, DeprecatedString const& value) override;
 
     virtual Gfx::Path& get_path() override;
 
diff --git a/Userland/Libraries/LibWeb/SVG/SVGPolylineElement.cpp b/Userland/Libraries/LibWeb/SVG/SVGPolylineElement.cpp
index c884c2623f4..17502219336 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGPolylineElement.cpp
+++ b/Userland/Libraries/LibWeb/SVG/SVGPolylineElement.cpp
@@ -22,7 +22,7 @@ void SVGPolylineElement::initialize(JS::Realm& realm)
     set_prototype(&Bindings::ensure_web_prototype<Bindings::SVGPolylineElementPrototype>(realm, "SVGPolylineElement"));
 }
 
-void SVGPolylineElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void SVGPolylineElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     SVGGeometryElement::attribute_changed(name, value);
 
diff --git a/Userland/Libraries/LibWeb/SVG/SVGPolylineElement.h b/Userland/Libraries/LibWeb/SVG/SVGPolylineElement.h
index 6e7d934a633..2580bc24377 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGPolylineElement.h
+++ b/Userland/Libraries/LibWeb/SVG/SVGPolylineElement.h
@@ -16,7 +16,7 @@ class SVGPolylineElement final : public SVGGeometryElement {
 public:
     virtual ~SVGPolylineElement() override = default;
 
-    virtual void attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value) override;
+    virtual void attribute_changed(FlyString const& name, DeprecatedString const& value) override;
 
     virtual Gfx::Path& get_path() override;
 
diff --git a/Userland/Libraries/LibWeb/SVG/SVGRadialGradientElement.cpp b/Userland/Libraries/LibWeb/SVG/SVGRadialGradientElement.cpp
index 9a7fa7181cd..aef6a0fd616 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGRadialGradientElement.cpp
+++ b/Userland/Libraries/LibWeb/SVG/SVGRadialGradientElement.cpp
@@ -21,7 +21,7 @@ void SVGRadialGradientElement::initialize(JS::Realm& realm)
     set_prototype(&Bindings::ensure_web_prototype<Bindings::SVGRadialGradientElementPrototype>(realm, "SVGRadialGradientElement"));
 }
 
-void SVGRadialGradientElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void SVGRadialGradientElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     SVGGradientElement::attribute_changed(name, value);
 
diff --git a/Userland/Libraries/LibWeb/SVG/SVGRadialGradientElement.h b/Userland/Libraries/LibWeb/SVG/SVGRadialGradientElement.h
index 55e50ff2ecb..50f40f28690 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGRadialGradientElement.h
+++ b/Userland/Libraries/LibWeb/SVG/SVGRadialGradientElement.h
@@ -18,7 +18,7 @@ class SVGRadialGradientElement : public SVGGradientElement {
 public:
     virtual ~SVGRadialGradientElement() override = default;
 
-    virtual void attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value) override;
+    virtual void attribute_changed(FlyString const& name, DeprecatedString const& value) override;
 
     virtual Optional<Gfx::PaintStyle const&> to_gfx_paint_style(SVGPaintContext const&) const override;
 
diff --git a/Userland/Libraries/LibWeb/SVG/SVGRectElement.cpp b/Userland/Libraries/LibWeb/SVG/SVGRectElement.cpp
index baf32a20892..d5124aaf137 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGRectElement.cpp
+++ b/Userland/Libraries/LibWeb/SVG/SVGRectElement.cpp
@@ -24,7 +24,7 @@ void SVGRectElement::initialize(JS::Realm& realm)
     set_prototype(&Bindings::ensure_web_prototype<Bindings::SVGRectElementPrototype>(realm, "SVGRectElement"));
 }
 
-void SVGRectElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void SVGRectElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     SVGGeometryElement::attribute_changed(name, value);
 
diff --git a/Userland/Libraries/LibWeb/SVG/SVGRectElement.h b/Userland/Libraries/LibWeb/SVG/SVGRectElement.h
index 9af6a7f50de..f5ad08615e1 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGRectElement.h
+++ b/Userland/Libraries/LibWeb/SVG/SVGRectElement.h
@@ -17,7 +17,7 @@ class SVGRectElement final : public SVGGeometryElement {
 public:
     virtual ~SVGRectElement() override = default;
 
-    virtual void attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value) override;
+    virtual void attribute_changed(FlyString const& name, DeprecatedString const& value) override;
 
     virtual Gfx::Path& get_path() override;
 
diff --git a/Userland/Libraries/LibWeb/SVG/SVGSVGElement.cpp b/Userland/Libraries/LibWeb/SVG/SVGSVGElement.cpp
index 722bf51e72a..ea956d6292c 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGSVGElement.cpp
+++ b/Userland/Libraries/LibWeb/SVG/SVGSVGElement.cpp
@@ -61,7 +61,7 @@ void SVGSVGElement::apply_presentational_hints(CSS::StyleProperties& style) cons
     }
 }
 
-void SVGSVGElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void SVGSVGElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     SVGGraphicsElement::attribute_changed(name, value);
 
diff --git a/Userland/Libraries/LibWeb/SVG/SVGSVGElement.h b/Userland/Libraries/LibWeb/SVG/SVGSVGElement.h
index df584b6e76f..a9c893a80b4 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGSVGElement.h
+++ b/Userland/Libraries/LibWeb/SVG/SVGSVGElement.h
@@ -36,7 +36,7 @@ private:
 
     virtual bool is_svg_svg_element() const override { return true; }
 
-    virtual void attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value) override;
+    virtual void attribute_changed(FlyString const& name, DeprecatedString const& value) override;
 
     void update_fallback_view_box_for_svg_as_image();
 
diff --git a/Userland/Libraries/LibWeb/SVG/SVGStopElement.cpp b/Userland/Libraries/LibWeb/SVG/SVGStopElement.cpp
index 452d4e600f1..50b273d80c4 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGStopElement.cpp
+++ b/Userland/Libraries/LibWeb/SVG/SVGStopElement.cpp
@@ -19,7 +19,7 @@ SVGStopElement::SVGStopElement(DOM::Document& document, DOM::QualifiedName quali
 {
 }
 
-void SVGStopElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void SVGStopElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     SVGElement::attribute_changed(name, value);
     if (name == SVG::AttributeNames::offset) {
diff --git a/Userland/Libraries/LibWeb/SVG/SVGStopElement.h b/Userland/Libraries/LibWeb/SVG/SVGStopElement.h
index 6b46791490f..8d822286668 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGStopElement.h
+++ b/Userland/Libraries/LibWeb/SVG/SVGStopElement.h
@@ -19,7 +19,7 @@ class SVGStopElement final : public SVGElement {
 public:
     virtual ~SVGStopElement() override = default;
 
-    virtual void attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value) override;
+    virtual void attribute_changed(FlyString const& name, DeprecatedString const& value) override;
 
     JS::NonnullGCPtr<SVGAnimatedNumber> offset() const;
 
diff --git a/Userland/Libraries/LibWeb/SVG/SVGSymbolElement.cpp b/Userland/Libraries/LibWeb/SVG/SVGSymbolElement.cpp
index 616b376caf2..c4cc5309bdf 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGSymbolElement.cpp
+++ b/Userland/Libraries/LibWeb/SVG/SVGSymbolElement.cpp
@@ -39,7 +39,7 @@ void SVGSymbolElement::apply_presentational_hints(CSS::StyleProperties& style) c
     }
 }
 
-void SVGSymbolElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void SVGSymbolElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     if (name.equals_ignoring_ascii_case(SVG::AttributeNames::viewBox))
         m_view_box = try_parse_view_box(value);
diff --git a/Userland/Libraries/LibWeb/SVG/SVGSymbolElement.h b/Userland/Libraries/LibWeb/SVG/SVGSymbolElement.h
index 7ce10c98475..313581e8847 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGSymbolElement.h
+++ b/Userland/Libraries/LibWeb/SVG/SVGSymbolElement.h
@@ -29,7 +29,7 @@ private:
 
     bool is_direct_child_of_use_shadow_tree() const;
 
-    virtual void attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value) override;
+    virtual void attribute_changed(FlyString const& name, DeprecatedString const& value) override;
 
     Optional<ViewBox> m_view_box;
 };
diff --git a/Userland/Libraries/LibWeb/SVG/SVGTextPositioningElement.cpp b/Userland/Libraries/LibWeb/SVG/SVGTextPositioningElement.cpp
index 879b0b9375a..b019526e338 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGTextPositioningElement.cpp
+++ b/Userland/Libraries/LibWeb/SVG/SVGTextPositioningElement.cpp
@@ -28,7 +28,7 @@ void SVGTextPositioningElement::initialize(JS::Realm& realm)
     set_prototype(&Bindings::ensure_web_prototype<Bindings::SVGTextPositioningElementPrototype>(realm, "SVGTextPositioningElement"));
 }
 
-void SVGTextPositioningElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void SVGTextPositioningElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     SVGGraphicsElement::attribute_changed(name, value);
 
diff --git a/Userland/Libraries/LibWeb/SVG/SVGTextPositioningElement.h b/Userland/Libraries/LibWeb/SVG/SVGTextPositioningElement.h
index 2742867988e..25d9ca631e6 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGTextPositioningElement.h
+++ b/Userland/Libraries/LibWeb/SVG/SVGTextPositioningElement.h
@@ -16,7 +16,7 @@ class SVGTextPositioningElement : public SVGTextContentElement {
     WEB_PLATFORM_OBJECT(SVGTextPositioningElement, SVGTextContentElement);
 
 public:
-    virtual void attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value) override;
+    virtual void attribute_changed(FlyString const& name, DeprecatedString const& value) override;
 
     Gfx::FloatPoint get_offset() const;
 
diff --git a/Userland/Libraries/LibWeb/SVG/SVGUseElement.cpp b/Userland/Libraries/LibWeb/SVG/SVGUseElement.cpp
index f64f049a9da..16e471f1ba0 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGUseElement.cpp
+++ b/Userland/Libraries/LibWeb/SVG/SVGUseElement.cpp
@@ -45,7 +45,7 @@ void SVGUseElement::visit_edges(Cell::Visitor& visitor)
     visitor.visit(m_document_observer);
 }
 
-void SVGUseElement::attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value)
+void SVGUseElement::attribute_changed(FlyString const& name, DeprecatedString const& value)
 {
     Base::attribute_changed(name, value);
 
diff --git a/Userland/Libraries/LibWeb/SVG/SVGUseElement.h b/Userland/Libraries/LibWeb/SVG/SVGUseElement.h
index 591221bc57a..6e4c21ce5d5 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGUseElement.h
+++ b/Userland/Libraries/LibWeb/SVG/SVGUseElement.h
@@ -19,7 +19,7 @@ class SVGUseElement final : public SVGGraphicsElement {
 public:
     virtual ~SVGUseElement() override = default;
 
-    virtual void attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value) override;
+    virtual void attribute_changed(FlyString const& name, DeprecatedString const& value) override;
 
     virtual void inserted() override;
 
diff --git a/Userland/Services/WebContent/WebDriverConnection.cpp b/Userland/Services/WebContent/WebDriverConnection.cpp
index 4cbfc3828fd..0a370466ba0 100644
--- a/Userland/Services/WebContent/WebDriverConnection.cpp
+++ b/Userland/Services/WebContent/WebDriverConnection.cpp
@@ -1064,18 +1064,16 @@ Messages::WebDriverClient::GetElementAttributeResponse WebDriverConnection::get_
     // 4. Let result be the result of the first matching condition:
     Optional<DeprecatedString> result;
 
-    auto deprecated_name = name.to_deprecated_string();
-
     // -> If name is a boolean attribute
-    if (Web::HTML::is_boolean_attribute(deprecated_name)) {
+    if (Web::HTML::is_boolean_attribute(name)) {
         // "true" (string) if the element has the attribute, otherwise null.
-        if (element->has_attribute(deprecated_name))
+        if (element->has_attribute(name))
             result = "true"sv;
     }
     // -> Otherwise
     else {
         // The result of getting an attribute by name name.
-        result = element->deprecated_get_attribute(deprecated_name);
+        result = element->deprecated_get_attribute(name);
     }
 
     // 5. Return success with data result.