diff --git a/Userland/Libraries/LibWeb/HTML/FormAssociatedElement.cpp b/Userland/Libraries/LibWeb/HTML/FormAssociatedElement.cpp
index 8e78a8a6dfb..3c991680621 100644
--- a/Userland/Libraries/LibWeb/HTML/FormAssociatedElement.cpp
+++ b/Userland/Libraries/LibWeb/HTML/FormAssociatedElement.cpp
@@ -166,18 +166,7 @@ void FormAssociatedElement::reset_form_owner()
 }
 
 // https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#concept-textarea/input-relevant-value
-String FormAssociatedElement::relevant_value() const
-{
-    auto const& html_element = form_associated_element_to_html_element();
-    if (is<HTMLInputElement>(html_element))
-        return static_cast<HTMLInputElement const&>(html_element).value();
-    if (is<HTMLTextAreaElement>(html_element))
-        return static_cast<HTMLTextAreaElement const&>(html_element).api_value();
-    VERIFY_NOT_REACHED();
-}
-
-// https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#concept-textarea/input-relevant-value
-void FormAssociatedElement::relevant_value_was_changed(JS::GCPtr<DOM::Text> text_node)
+void FormAssociatedTextControlElement::relevant_value_was_changed(JS::GCPtr<DOM::Text> text_node)
 {
     auto the_relevant_value = relevant_value();
     auto relevant_value_length = the_relevant_value.code_points().length();
@@ -214,7 +203,7 @@ void FormAssociatedElement::relevant_value_was_changed(JS::GCPtr<DOM::Text> text
 }
 
 // https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#dom-textarea/input-select
-WebIDL::ExceptionOr<void> FormAssociatedElement::select()
+WebIDL::ExceptionOr<void> FormAssociatedTextControlElement::select()
 {
     // 1. If this element is an input element, and either select() does not apply to this element
     //    or the corresponding control has no selectable text, return.
@@ -232,7 +221,7 @@ WebIDL::ExceptionOr<void> FormAssociatedElement::select()
 }
 
 // https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#dom-textarea/input-selectionstart
-Optional<WebIDL::UnsignedLong> FormAssociatedElement::selection_start() const
+Optional<WebIDL::UnsignedLong> FormAssociatedTextControlElement::selection_start() const
 {
     // 1. If this element is an input element, and selectionStart does not apply to this element, return null.
     auto const& html_element = form_associated_element_to_html_element();
@@ -255,7 +244,7 @@ Optional<WebIDL::UnsignedLong> FormAssociatedElement::selection_start() const
 }
 
 // https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#textFieldSelection:dom-textarea/input-selectionstart-2
-WebIDL::ExceptionOr<void> FormAssociatedElement::set_selection_start(Optional<WebIDL::UnsignedLong> const& value)
+WebIDL::ExceptionOr<void> FormAssociatedTextControlElement::set_selection_start(Optional<WebIDL::UnsignedLong> const& value)
 {
     // 1. If this element is an input element, and selectionStart does not apply to this element,
     //    throw an "InvalidStateError" DOMException.
@@ -280,7 +269,7 @@ WebIDL::ExceptionOr<void> FormAssociatedElement::set_selection_start(Optional<We
 }
 
 // https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#dom-textarea/input-selectionend
-Optional<WebIDL::UnsignedLong> FormAssociatedElement::selection_end() const
+Optional<WebIDL::UnsignedLong> FormAssociatedTextControlElement::selection_end() const
 {
     // 1. If this element is an input element, and selectionEnd does not apply to this element, return
     //    null.
@@ -304,7 +293,7 @@ Optional<WebIDL::UnsignedLong> FormAssociatedElement::selection_end() const
 }
 
 // https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#textFieldSelection:dom-textarea/input-selectionend-3
-WebIDL::ExceptionOr<void> FormAssociatedElement::set_selection_end(Optional<WebIDL::UnsignedLong> const& value)
+WebIDL::ExceptionOr<void> FormAssociatedTextControlElement::set_selection_end(Optional<WebIDL::UnsignedLong> const& value)
 {
     // 1. If this element is an input element, and selectionEnd does not apply to this element,
     //    throw an "InvalidStateError" DOMException.
@@ -322,7 +311,7 @@ WebIDL::ExceptionOr<void> FormAssociatedElement::set_selection_end(Optional<WebI
 }
 
 // https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#selection-direction
-Optional<String> FormAssociatedElement::selection_direction() const
+Optional<String> FormAssociatedTextControlElement::selection_direction() const
 {
     // 1. If this element is an input element, and selectionDirection does not apply to this
     //    element, return null.
@@ -347,7 +336,7 @@ Optional<String> FormAssociatedElement::selection_direction() const
 }
 
 // https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#set-the-selection-direction
-void FormAssociatedElement::set_selection_direction(Optional<String> direction)
+void FormAssociatedTextControlElement::set_selection_direction(Optional<String> direction)
 {
     // To set the selection direction of an element to a given direction, update the element's
     // selection direction to the given direction, unless the direction is "none" and the
@@ -357,7 +346,7 @@ void FormAssociatedElement::set_selection_direction(Optional<String> direction)
 }
 
 // https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#dom-textarea/input-setselectionrange
-WebIDL::ExceptionOr<void> FormAssociatedElement::set_selection_range(Optional<WebIDL::UnsignedLong> start, Optional<WebIDL::UnsignedLong> end, Optional<String> direction)
+WebIDL::ExceptionOr<void> FormAssociatedTextControlElement::set_selection_range(Optional<WebIDL::UnsignedLong> start, Optional<WebIDL::UnsignedLong> end, Optional<String> direction)
 {
     // 1. If this element is an input element, and setSelectionRange() does not apply to this
     //    element, throw an "InvalidStateError" DOMException.
@@ -371,7 +360,7 @@ WebIDL::ExceptionOr<void> FormAssociatedElement::set_selection_range(Optional<We
 }
 
 // https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#set-the-selection-range
-void FormAssociatedElement::set_the_selection_range(Optional<WebIDL::UnsignedLong> start, Optional<WebIDL::UnsignedLong> end, SelectionDirection direction)
+void FormAssociatedTextControlElement::set_the_selection_range(Optional<WebIDL::UnsignedLong> start, Optional<WebIDL::UnsignedLong> end, SelectionDirection direction)
 {
     // 1. If start is null, let start be zero.
     start = start.value_or(0);
diff --git a/Userland/Libraries/LibWeb/HTML/FormAssociatedElement.h b/Userland/Libraries/LibWeb/HTML/FormAssociatedElement.h
index 30747c6d928..133facfea2e 100644
--- a/Userland/Libraries/LibWeb/HTML/FormAssociatedElement.h
+++ b/Userland/Libraries/LibWeb/HTML/FormAssociatedElement.h
@@ -91,15 +91,40 @@ public:
 
     virtual String value() const { return String {}; }
 
-    // https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#concept-textarea/input-relevant-value
-    String relevant_value() const;
-
     virtual HTMLElement& form_associated_element_to_html_element() = 0;
     HTMLElement const& form_associated_element_to_html_element() const { return const_cast<FormAssociatedElement&>(*this).form_associated_element_to_html_element(); }
 
     // https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#concept-form-reset-control
     virtual void reset_algorithm() {};
 
+protected:
+    FormAssociatedElement() = default;
+    virtual ~FormAssociatedElement() = default;
+
+    virtual void form_associated_element_was_inserted() { }
+    virtual void form_associated_element_was_removed(DOM::Node*) { }
+    virtual void form_associated_element_attribute_changed(FlyString const&, Optional<String> const&) { }
+
+    void form_node_was_inserted();
+    void form_node_was_removed();
+    void form_node_attribute_changed(FlyString const&, Optional<String> const&);
+
+    virtual void selection_was_changed() { }
+
+private:
+    void reset_form_owner();
+
+    WeakPtr<HTMLFormElement> m_form;
+
+    // https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#parser-inserted-flag
+    bool m_parser_inserted { false };
+};
+
+class FormAssociatedTextControlElement : public FormAssociatedElement {
+public:
+    // https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#concept-textarea/input-relevant-value
+    virtual String relevant_value() = 0;
+
     // https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#dom-textarea/input-select
     WebIDL::ExceptionOr<void> select();
 
@@ -123,30 +148,10 @@ public:
     WebIDL::ExceptionOr<void> set_selection_range(Optional<WebIDL::UnsignedLong> start, Optional<WebIDL::UnsignedLong> end, Optional<String> direction);
 
 protected:
-    FormAssociatedElement() = default;
-    virtual ~FormAssociatedElement() = default;
-
-    virtual void form_associated_element_was_inserted() { }
-    virtual void form_associated_element_was_removed(DOM::Node*) { }
-    virtual void form_associated_element_attribute_changed(FlyString const&, Optional<String> const&) { }
-
-    void form_node_was_inserted();
-    void form_node_was_removed();
-    void form_node_attribute_changed(FlyString const&, Optional<String> const&);
-
     // https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#concept-textarea/input-relevant-value
     void relevant_value_was_changed(JS::GCPtr<DOM::Text>);
 
-    virtual void selection_was_changed() { }
-
 private:
-    void reset_form_owner();
-
-    WeakPtr<HTMLFormElement> m_form;
-
-    // https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#parser-inserted-flag
-    bool m_parser_inserted { false };
-
     // https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#concept-textarea/input-selection
     WebIDL::UnsignedLong m_selection_start { 0 };
     WebIDL::UnsignedLong m_selection_end { 0 };
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLInputElement.h b/Userland/Libraries/LibWeb/HTML/HTMLInputElement.h
index 9c75cb65c89..e3a6c0a0925 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLInputElement.h
+++ b/Userland/Libraries/LibWeb/HTML/HTMLInputElement.h
@@ -49,7 +49,7 @@ namespace Web::HTML {
 
 class HTMLInputElement final
     : public HTMLElement
-    , public FormAssociatedElement
+    , public FormAssociatedTextControlElement
     , public DOM::EditableTextNodeOwner
     , public Layout::ImageProvider {
     WEB_PLATFORM_OBJECT(HTMLInputElement, HTMLElement);
@@ -77,6 +77,9 @@ public:
     virtual String value() const override;
     WebIDL::ExceptionOr<void> set_value(String const&);
 
+    // https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#concept-textarea/input-relevant-value
+    virtual String relevant_value() override { return value(); }
+
     void commit_pending_changes();
 
     String placeholder() const;
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLTextAreaElement.h b/Userland/Libraries/LibWeb/HTML/HTMLTextAreaElement.h
index be0d7683e2a..79948316761 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLTextAreaElement.h
+++ b/Userland/Libraries/LibWeb/HTML/HTMLTextAreaElement.h
@@ -20,7 +20,7 @@ namespace Web::HTML {
 
 class HTMLTextAreaElement final
     : public HTMLElement
-    , public FormAssociatedElement
+    , public FormAssociatedTextControlElement
     , public DOM::EditableTextNodeOwner {
     WEB_PLATFORM_OBJECT(HTMLTextAreaElement, HTMLElement);
     JS_DECLARE_ALLOCATOR(HTMLTextAreaElement);
@@ -84,6 +84,9 @@ public:
     // https://html.spec.whatwg.org/multipage/form-elements.html#the-textarea-element:concept-fe-api-value-3
     String api_value() const;
 
+    // https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#concept-textarea/input-relevant-value
+    virtual String relevant_value() override { return api_value(); }
+
     u32 text_length() const;
 
     bool check_validity();
diff --git a/Userland/Libraries/LibWeb/Page/EventHandler.cpp b/Userland/Libraries/LibWeb/Page/EventHandler.cpp
index 92d2a920ea2..28c98f5698f 100644
--- a/Userland/Libraries/LibWeb/Page/EventHandler.cpp
+++ b/Userland/Libraries/LibWeb/Page/EventHandler.cpp
@@ -1159,7 +1159,7 @@ void EventHandler::update_selection_range_for_input_or_textarea()
     // FIXME: support selection directions other than ::Forward
     auto direction = HTML::SelectionDirection::Forward;
 
-    Optional<HTML::FormAssociatedElement&> target {};
+    Optional<HTML::FormAssociatedTextControlElement&> target {};
     if (is<HTML::HTMLInputElement>(shadow_host))
         target = static_cast<HTML::HTMLInputElement&>(shadow_host);
     else if (is<HTML::HTMLTextAreaElement>(shadow_host))