diff --git a/Libraries/LibWeb/HTML/AttributeNames.h b/Libraries/LibWeb/HTML/AttributeNames.h
index 3aa23cb82b4..26ab6d49c19 100644
--- a/Libraries/LibWeb/HTML/AttributeNames.h
+++ b/Libraries/LibWeb/HTML/AttributeNames.h
@@ -26,6 +26,7 @@ namespace AttributeNames {
     __ENUMERATE_HTML_ATTRIBUTE(archive, "archive")                                       \
     __ENUMERATE_HTML_ATTRIBUTE(as, "as")                                                 \
     __ENUMERATE_HTML_ATTRIBUTE(async, "async")                                           \
+    __ENUMERATE_HTML_ATTRIBUTE(autocapitalize, "autocapitalize")                         \
     __ENUMERATE_HTML_ATTRIBUTE(autocomplete, "autocomplete")                             \
     __ENUMERATE_HTML_ATTRIBUTE(autofocus, "autofocus")                                   \
     __ENUMERATE_HTML_ATTRIBUTE(autoplay, "autoplay")                                     \
diff --git a/Libraries/LibWeb/HTML/HTMLElement.cpp b/Libraries/LibWeb/HTML/HTMLElement.cpp
index c669132d945..0988c5b7dfc 100644
--- a/Libraries/LibWeb/HTML/HTMLElement.cpp
+++ b/Libraries/LibWeb/HTML/HTMLElement.cpp
@@ -2232,4 +2232,97 @@ void HTMLElement::set_writing_suggestions(String const& given_value)
     MUST(set_attribute(HTML::AttributeNames::writingsuggestions, given_value));
 }
 
+// https://html.spec.whatwg.org/multipage/interaction.html#own-autocapitalization-hint
+HTMLElement::AutocapitalizationHint HTMLElement::own_autocapitalization_hint() const
+{
+    // The autocapitalization processing model is based on selecting among five autocapitalization hints, defined as follows:
+    //
+    // default
+    //     The user agent and input method should make their own determination of whether or not to enable autocapitalization.
+    // none
+    //     No autocapitalization should be applied (all letters should default to lowercase).
+    // sentences
+    //     The first letter of each sentence should default to a capital letter; all other letters should default to lowercase.
+    // words
+    //     The first letter of each word should default to a capital letter; all other letters should default to lowercase.
+    // characters
+    //     All letters should default to uppercase.
+
+    // The autocapitalize attribute is an enumerated attribute whose states are the possible autocapitalization hints.
+    // The autocapitalization hint specified by the attribute's state combines with other considerations to form the
+    // used autocapitalization hint, which informs the behavior of the user agent. The keywords for this attribute and
+    // their state mappings are as follows:
+
+    // Keyword    | State
+    // off        | none
+    // none       |
+    // on         | sentences
+    // sentences  |
+    // words      | words
+    // characters | characters
+
+    // The attribute's missing value default is the default state, and its invalid value default is the sentences state.
+
+    // To compute the own autocapitalization hint of an element element, run the following steps:
+    // 1. If the autocapitalize content attribute is present on element, and its value is not the empty string, return the
+    //    state of the attribute.
+    auto maybe_autocapitalize_attribute = attribute(HTML::AttributeNames::autocapitalize);
+
+    if (maybe_autocapitalize_attribute.has_value() && !maybe_autocapitalize_attribute.value().is_empty()) {
+        auto autocapitalize_attribute_string_view = maybe_autocapitalize_attribute.value().bytes_as_string_view();
+
+        if (autocapitalize_attribute_string_view.is_one_of_ignoring_ascii_case("off"sv, "none"sv))
+            return AutocapitalizationHint::None;
+
+        if (autocapitalize_attribute_string_view.equals_ignoring_ascii_case("words"sv))
+            return AutocapitalizationHint::Words;
+
+        if (autocapitalize_attribute_string_view.equals_ignoring_ascii_case("characters"sv))
+            return AutocapitalizationHint::Characters;
+
+        return AutocapitalizationHint::Sentences;
+    }
+
+    // If element is an autocapitalize-and-autocorrect inheriting element and has a non-null form owner, return the own autocapitalization hint of element's form owner.
+    auto const* form_associated_element = as_if<FormAssociatedElement>(this);
+    if (form_associated_element && form_associated_element->is_autocapitalize_and_autocorrect_inheriting() && form_associated_element->form())
+        return form_associated_element->form()->own_autocapitalization_hint();
+
+    // 3. Return default.
+    return AutocapitalizationHint::Default;
+}
+
+// https://html.spec.whatwg.org/multipage/interaction.html#attr-autocapitalize
+String HTMLElement::autocapitalize() const
+{
+    // The autocapitalize getter steps are to:
+    // 1. Let state be the own autocapitalization hint of this.
+    auto state = own_autocapitalization_hint();
+
+    // 2. If state is default, then return the empty string.
+    // 3. If state is none, then return "none".
+    // 4. If state is sentences, then return "sentences".
+    // 5. Return the keyword value corresponding to state.
+    switch (state) {
+    case AutocapitalizationHint::Default:
+        return String {};
+    case AutocapitalizationHint::None:
+        return "none"_string;
+    case AutocapitalizationHint::Sentences:
+        return "sentences"_string;
+    case AutocapitalizationHint::Words:
+        return "words"_string;
+    case AutocapitalizationHint::Characters:
+        return "characters"_string;
+    }
+
+    VERIFY_NOT_REACHED();
+}
+
+void HTMLElement::set_autocapitalize(String const& given_value)
+{
+    // The autocapitalize setter steps are to set the autocapitalize content attribute to the given value.
+    MUST(set_attribute(HTML::AttributeNames::autocapitalize, given_value));
+}
+
 }
diff --git a/Libraries/LibWeb/HTML/HTMLElement.h b/Libraries/LibWeb/HTML/HTMLElement.h
index cd2807214c9..03aea314a70 100644
--- a/Libraries/LibWeb/HTML/HTMLElement.h
+++ b/Libraries/LibWeb/HTML/HTMLElement.h
@@ -123,6 +123,18 @@ public:
     String writing_suggestions() const;
     void set_writing_suggestions(String const&);
 
+    enum class AutocapitalizationHint {
+        Default,
+        None,
+        Sentences,
+        Words,
+        Characters
+    };
+
+    AutocapitalizationHint own_autocapitalization_hint() const;
+    String autocapitalize() const;
+    void set_autocapitalize(String const&);
+
     bool fire_a_synthetic_pointer_event(FlyString const& type, DOM::Element& target, bool not_trusted);
 
     // https://html.spec.whatwg.org/multipage/forms.html#category-label
diff --git a/Libraries/LibWeb/HTML/HTMLElement.idl b/Libraries/LibWeb/HTML/HTMLElement.idl
index b2b43c346dc..ff0f1d44032 100644
--- a/Libraries/LibWeb/HTML/HTMLElement.idl
+++ b/Libraries/LibWeb/HTML/HTMLElement.idl
@@ -26,7 +26,7 @@ interface HTMLElement : Element {
     [CEReactions] attribute boolean draggable;
     [CEReactions] attribute boolean spellcheck;
     [CEReactions] attribute DOMString writingSuggestions;
-    [FIXME, CEReactions] attribute DOMString autocapitalize;
+    [CEReactions] attribute DOMString autocapitalize;
     [FIXME, CEReactions] attribute boolean autocorrect;
 
     [LegacyNullToEmptyString, CEReactions] attribute Utf16DOMString innerText;
diff --git a/Tests/LibWeb/Text/expected/wpt-import/html/editing/editing-0/autocapitalization/autocapitalize.txt b/Tests/LibWeb/Text/expected/wpt-import/html/editing/editing-0/autocapitalization/autocapitalize.txt
new file mode 100644
index 00000000000..2a0db180b52
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/wpt-import/html/editing/editing-0/autocapitalization/autocapitalize.txt
@@ -0,0 +1,13 @@
+Harness status: OK
+
+Found 8 tests
+
+8 Pass
+Pass	Test that the autocapitalize is available on HTMLInputElement.
+Pass	Test that the autocapitalize is available on HTMLTextAreaElement.
+Pass	Test that the autocapitalize is available on div.
+Pass	Test deprecated values of autocapitalize.
+Pass	Test reflection of autocapitalize.
+Pass	Test that the IDL attribute returns the empty string if the content attribute is not set.
+Pass	Test inheriting values from a form.
+Pass	Verify that even input types that are never autocapitalized support the IDL interface.
\ No newline at end of file
diff --git a/Tests/LibWeb/Text/input/wpt-import/html/editing/editing-0/autocapitalization/autocapitalize.html b/Tests/LibWeb/Text/input/wpt-import/html/editing/editing-0/autocapitalization/autocapitalize.html
new file mode 100644
index 00000000000..50c9ffbec18
--- /dev/null
+++ b/Tests/LibWeb/Text/input/wpt-import/html/editing/editing-0/autocapitalization/autocapitalize.html
@@ -0,0 +1,688 @@
+<!DOCTYPE html>
+<html>
+<link rel="help" href="https://html.spec.whatwg.org/multipage/interaction.html#autocapitalization">
+<body>
+<script src="../../../../resources/testharness.js"></script>
+<script src="../../../../resources/testharnessreport.js"></script>
+<script>
+
+test(function() {
+    assert_true('autocapitalize' in document.createElement('input'));
+}, "Test that the autocapitalize is available on HTMLInputElement.")
+
+test(function() {
+    assert_true('autocapitalize' in document.createElement('textarea'));
+}, "Test that the autocapitalize is available on HTMLTextAreaElement.")
+
+test(function() {
+    assert_true('autocapitalize' in document.createElement('div'));
+}, "Test that the autocapitalize is available on div.")
+
+test(function() {
+  var elements = [ document.createElement('input'),
+                   document.createElement('textarea'),
+                   document.createElement('div') ];
+
+  elements.forEach(function(e) {
+    e.autocapitalize = 'on';
+    assert_equals(e.autocapitalize, 'sentences');
+
+    e.autocapitalize = 'off';
+    assert_equals(e.autocapitalize, 'none');
+  });
+}, "Test deprecated values of autocapitalize.");
+
+test(function() {
+  var elements = [ document.createElement('input'),
+                   document.createElement('textarea'),
+                   document.createElement('div') ];
+  var knownValues = [ 'none', 'characters', 'words', 'sentences' ];
+
+  elements.forEach(function(e) {
+    // Default value.
+    assert_equals(e.autocapitalize, '');
+
+    // Empty value.
+    e.autocapitalize = '';
+    assert_equals(e.autocapitalize, '');
+    assert_equals(e.getAttribute('autocapitalize'), '');
+    e.setAttribute('autocapitalize', '');
+    assert_equals(e.autocapitalize, '');
+    assert_equals(e.getAttribute('autocapitalize'), '');
+    assert_equals(e.autocapitalize, '');
+
+    // Invalid value.
+    e.autocapitalize = 'foo';
+    assert_equals(e.autocapitalize, 'sentences');
+    assert_equals(e.getAttribute('autocapitalize'), 'foo');
+    e.setAttribute('autocapitalize', 'bar');
+    assert_equals(e.autocapitalize, 'sentences');
+    assert_equals(e.getAttribute('autocapitalize'), 'bar');
+
+    // Default value.
+    e.removeAttribute('autocapitalize');
+    assert_equals(e.autocapitalize, '');
+    assert_equals(e.getAttribute('autocapitalize'), null);
+
+    // Case insensitive.
+    e.setAttribute('autocapitalize', 'NoNe');
+    assert_equals(e.autocapitalize, 'none');
+    assert_equals(e.getAttribute('autocapitalize'), 'NoNe');
+    e.autocapitalize = 'WORDS';
+    assert_equals(e.autocapitalize, 'words');
+    assert_equals(e.getAttribute('autocapitalize'), 'WORDS');
+
+    knownValues.forEach(function(value) {
+      e.setAttribute('autocapitalize', value);
+      assert_equals(e.autocapitalize, value);
+      assert_equals(e.getAttribute('autocapitalize'), value);
+
+      e.removeAttribute('autocapitalize');
+
+      e.autocapitalize = value;
+      assert_equals(e.autocapitalize, value);
+      assert_equals(e.getAttribute('autocapitalize'), value);
+
+      e.removeAttribute('autocapitalize');
+    });
+  });
+}, "Test reflection of autocapitalize.");
+
+test(function() {
+var testData = [ 'text',
+                 'search',
+                 'email',
+                 'url',
+                 'tel',
+                 'number',
+                 'date',
+                 'color',
+                 'password' ];
+
+  testData.forEach(function(data) {
+    const input = document.createElement('input');
+    input.type = data;
+    assert_equals(input.autocapitalize, '');
+
+    // Verify that wrapping the input element in a form doesn't change the
+    // defaults.
+    const form = document.createElement('form');
+    form.appendChild(input);
+    assert_equals(input.autocapitalize, '');
+  });
+}, "Test that the IDL attribute returns the empty string if the content "
++ "attribute is not set.")
+
+test(function() {
+  const testData = [
+    {
+      formValue: null,
+      formElementValue: null,
+      inheritedResult: '',
+      uninheritedResult: '',
+    },
+    {
+      formValue: null,
+      formElementValue: '',
+      inheritedResult: '',
+      uninheritedResult: '',
+    },
+    {
+      formValue: null,
+      formElementValue: 'on',
+      inheritedResult: 'sentences',
+      uninheritedResult: 'sentences',
+    },
+    {
+      formValue: null,
+      formElementValue: 'off',
+      inheritedResult: 'none',
+      uninheritedResult: 'none',
+    },
+    {
+      formValue: null,
+      formElementValue: 'none',
+      inheritedResult: 'none',
+      uninheritedResult: 'none',
+    },
+    {
+      formValue: null,
+      formElementValue: 'characters',
+      inheritedResult: 'characters',
+      uninheritedResult: 'characters',
+    },
+    {
+      formValue: null,
+      formElementValue: 'words',
+      inheritedResult: 'words',
+      uninheritedResult: 'words',
+    },
+    {
+      formValue: null,
+      formElementValue: 'sentences',
+      inheritedResult: 'sentences',
+      uninheritedResult: 'sentences',
+    },
+    {
+      formValue: null,
+      formElementValue: 'foo',
+      inheritedResult: 'sentences',
+      uninheritedResult: 'sentences',
+    },
+    {
+      formValue: '',
+      formElementValue: null,
+      inheritedResult: '',
+      uninheritedResult: '',
+    },
+    {
+      formValue: '',
+      formElementValue: '',
+      inheritedResult: '',
+      uninheritedResult: '',
+    },
+    {
+      formValue: '',
+      formElementValue: 'on',
+      inheritedResult: 'sentences',
+      uninheritedResult: 'sentences',
+    },
+    {
+      formValue: '',
+      formElementValue: 'off',
+      inheritedResult: 'none',
+      uninheritedResult: 'none',
+    },
+    {
+      formValue: '',
+      formElementValue: 'none',
+      inheritedResult: 'none',
+      uninheritedResult: 'none',
+    },
+    {
+      formValue: '',
+      formElementValue: 'characters',
+      inheritedResult: 'characters',
+      uninheritedResult: 'characters',
+    },
+    {
+      formValue: '',
+      formElementValue: 'words',
+      inheritedResult: 'words',
+      uninheritedResult: 'words',
+    },
+    {
+      formValue: '',
+      formElementValue: 'sentences',
+      inheritedResult: 'sentences',
+      uninheritedResult: 'sentences',
+    },
+    {
+      formValue: '',
+      formElementValue: 'foo',
+      inheritedResult: 'sentences',
+      uninheritedResult: 'sentences',
+    },
+    {
+      formValue: 'on',
+      formElementValue: null,
+      inheritedResult: 'sentences',
+      uninheritedResult: '',
+    },
+    {
+      formValue: 'on',
+      formElementValue: '',
+      inheritedResult: 'sentences',
+      uninheritedResult: '',
+    },
+    {
+      formValue: 'on',
+      formElementValue: 'on',
+      inheritedResult: 'sentences',
+      uninheritedResult: 'sentences',
+    },
+    {
+      formValue: 'on',
+      formElementValue: 'off',
+      inheritedResult: 'none',
+      uninheritedResult: 'none',
+    },
+    {
+      formValue: 'on',
+      formElementValue: 'none',
+      inheritedResult: 'none',
+      uninheritedResult: 'none',
+    },
+    {
+      formValue: 'on',
+      formElementValue: 'characters',
+      inheritedResult: 'characters',
+      uninheritedResult: 'characters',
+    },
+    {
+      formValue: 'on',
+      formElementValue: 'words',
+      inheritedResult: 'words',
+      uninheritedResult: 'words',
+    },
+    {
+      formValue: 'on',
+      formElementValue: 'sentences',
+      inheritedResult: 'sentences',
+      uninheritedResult: 'sentences',
+    },
+    {
+      formValue: 'on',
+      formElementValue: 'foo',
+      inheritedResult: 'sentences',
+      uninheritedResult: 'sentences',
+    },
+    {
+      formValue: 'off',
+      formElementValue: null,
+      inheritedResult: 'none',
+      uninheritedResult: '',
+    },
+    {
+      formValue: 'off',
+      formElementValue: '',
+      inheritedResult: 'none',
+      uninheritedResult: '',
+    },
+    {
+      formValue: 'off',
+      formElementValue: 'on',
+      inheritedResult: 'sentences',
+      uninheritedResult: 'sentences',
+    },
+    {
+      formValue: 'off',
+      formElementValue: 'off',
+      inheritedResult: 'none',
+      uninheritedResult: 'none',
+    },
+    {
+      formValue: 'off',
+      formElementValue: 'none',
+      inheritedResult: 'none',
+      uninheritedResult: 'none',
+    },
+    {
+      formValue: 'off',
+      formElementValue: 'characters',
+      inheritedResult: 'characters',
+      uninheritedResult: 'characters',
+    },
+    {
+      formValue: 'off',
+      formElementValue: 'words',
+      inheritedResult: 'words',
+      uninheritedResult: 'words',
+    },
+    {
+      formValue: 'off',
+      formElementValue: 'sentences',
+      inheritedResult: 'sentences',
+      uninheritedResult: 'sentences',
+    },
+    {
+      formValue: 'off',
+      formElementValue: 'foo',
+      inheritedResult: 'sentences',
+      uninheritedResult: 'sentences',
+    },
+    {
+      formValue: 'none',
+      formElementValue: null,
+      inheritedResult: 'none',
+      uninheritedResult: '',
+    },
+    {
+      formValue: 'none',
+      formElementValue: '',
+      inheritedResult: 'none',
+      uninheritedResult: '',
+    },
+    {
+      formValue: 'none',
+      formElementValue: 'on',
+      inheritedResult: 'sentences',
+      uninheritedResult: 'sentences',
+    },
+    {
+      formValue: 'none',
+      formElementValue: 'off',
+      inheritedResult: 'none',
+      uninheritedResult: 'none',
+    },
+    {
+      formValue: 'none',
+      formElementValue: 'none',
+      inheritedResult: 'none',
+      uninheritedResult: 'none',
+    },
+    {
+      formValue: 'none',
+      formElementValue: 'characters',
+      inheritedResult: 'characters',
+      uninheritedResult: 'characters',
+    },
+    {
+      formValue: 'none',
+      formElementValue: 'words',
+      inheritedResult: 'words',
+      uninheritedResult: 'words',
+    },
+    {
+      formValue: 'none',
+      formElementValue: 'sentences',
+      inheritedResult: 'sentences',
+      uninheritedResult: 'sentences',
+    },
+    {
+      formValue: 'none',
+      formElementValue: 'foo',
+      inheritedResult: 'sentences',
+      uninheritedResult: 'sentences',
+    },
+    {
+      formValue: 'characters',
+      formElementValue: null,
+      inheritedResult: 'characters',
+      uninheritedResult: '',
+    },
+    {
+      formValue: 'characters',
+      formElementValue: '',
+      inheritedResult: 'characters',
+      uninheritedResult: '',
+    },
+    {
+      formValue: 'characters',
+      formElementValue: 'on',
+      inheritedResult: 'sentences',
+      uninheritedResult: 'sentences',
+    },
+    {
+      formValue: 'characters',
+      formElementValue: 'off',
+      inheritedResult: 'none',
+      uninheritedResult: 'none',
+    },
+    {
+      formValue: 'characters',
+      formElementValue: 'none',
+      inheritedResult: 'none',
+      uninheritedResult: 'none',
+    },
+    {
+      formValue: 'characters',
+      formElementValue: 'characters',
+      inheritedResult: 'characters',
+      uninheritedResult: 'characters',
+    },
+    {
+      formValue: 'characters',
+      formElementValue: 'words',
+      inheritedResult: 'words',
+      uninheritedResult: 'words',
+    },
+    {
+      formValue: 'characters',
+      formElementValue: 'sentences',
+      inheritedResult: 'sentences',
+      uninheritedResult: 'sentences',
+    },
+    {
+      formValue: 'characters',
+      formElementValue: 'foo',
+      inheritedResult: 'sentences',
+      uninheritedResult: 'sentences',
+    },
+    {
+      formValue: 'words',
+      formElementValue: null,
+      inheritedResult: 'words',
+      uninheritedResult: '',
+    },
+    {
+      formValue: 'words',
+      formElementValue: '',
+      inheritedResult: 'words',
+      uninheritedResult: '',
+    },
+    {
+      formValue: 'words',
+      formElementValue: 'on',
+      inheritedResult: 'sentences',
+      uninheritedResult: 'sentences',
+    },
+    {
+      formValue: 'words',
+      formElementValue: 'off',
+      inheritedResult: 'none',
+      uninheritedResult: 'none',
+    },
+    {
+      formValue: 'words',
+      formElementValue: 'none',
+      inheritedResult: 'none',
+      uninheritedResult: 'none',
+    },
+    {
+      formValue: 'words',
+      formElementValue: 'characters',
+      inheritedResult: 'characters',
+      uninheritedResult: 'characters',
+    },
+    {
+      formValue: 'words',
+      formElementValue: 'words',
+      inheritedResult: 'words',
+      uninheritedResult: 'words',
+    },
+    {
+      formValue: 'words',
+      formElementValue: 'sentences',
+      inheritedResult: 'sentences',
+      uninheritedResult: 'sentences',
+    },
+    {
+      formValue: 'words',
+      formElementValue: 'foo',
+      inheritedResult: 'sentences',
+      uninheritedResult: 'sentences',
+    },
+    {
+      formValue: 'sentences',
+      formElementValue: null,
+      inheritedResult: 'sentences',
+      uninheritedResult: '',
+    },
+    {
+      formValue: 'sentences',
+      formElementValue: '',
+      inheritedResult: 'sentences',
+      uninheritedResult: '',
+    },
+    {
+      formValue: 'sentences',
+      formElementValue: 'on',
+      inheritedResult: 'sentences',
+      uninheritedResult: 'sentences',
+    },
+    {
+      formValue: 'sentences',
+      formElementValue: 'off',
+      inheritedResult: 'none',
+      uninheritedResult: 'none',
+    },
+    {
+      formValue: 'sentences',
+      formElementValue: 'none',
+      inheritedResult: 'none',
+      uninheritedResult: 'none',
+    },
+    {
+      formValue: 'sentences',
+      formElementValue: 'characters',
+      inheritedResult: 'characters',
+      uninheritedResult: 'characters',
+    },
+    {
+      formValue: 'sentences',
+      formElementValue: 'words',
+      inheritedResult: 'words',
+      uninheritedResult: 'words',
+    },
+    {
+      formValue: 'sentences',
+      formElementValue: 'sentences',
+      inheritedResult: 'sentences',
+      uninheritedResult: 'sentences',
+    },
+    {
+      formValue: 'sentences',
+      formElementValue: 'foo',
+      inheritedResult: 'sentences',
+      uninheritedResult: 'sentences',
+    },
+    {
+      formValue: 'foo',
+      formElementValue: null,
+      inheritedResult: 'sentences',
+      uninheritedResult: '',
+    },
+    {
+      formValue: 'foo',
+      formElementValue: '',
+      inheritedResult: 'sentences',
+      uninheritedResult: '',
+    },
+    {
+      formValue: 'foo',
+      formElementValue: 'on',
+      inheritedResult: 'sentences',
+      uninheritedResult: 'sentences',
+    },
+    {
+      formValue: 'foo',
+      formElementValue: 'off',
+      inheritedResult: 'none',
+      uninheritedResult: 'none',
+    },
+    {
+      formValue: 'foo',
+      formElementValue: 'none',
+      inheritedResult: 'none',
+      uninheritedResult: 'none',
+    },
+    {
+      formValue: 'foo',
+      formElementValue: 'characters',
+      inheritedResult: 'characters',
+      uninheritedResult: 'characters',
+    },
+    {
+      formValue: 'foo',
+      formElementValue: 'words',
+      inheritedResult: 'words',
+      uninheritedResult: 'words',
+    },
+    {
+      formValue: 'foo',
+      formElementValue: 'sentences',
+      inheritedResult: 'sentences',
+      uninheritedResult: 'sentences',
+    },
+    {
+      formValue: 'foo',
+      formElementValue: 'foo',
+      inheritedResult: 'sentences',
+      uninheritedResult: 'sentences',
+    },
+  ];
+
+  const formElements = [
+    {element: 'button', inherits: true},
+    {element: 'fieldset', inherits: true},
+    {element: 'img', inherits: false},
+    {element: 'input', inherits: true},
+    {element: 'object', inherits: false},
+    {element: 'output', inherits: true},
+    {element: 'select', inherits: true},
+    {element: 'textarea', inherits: true},
+  ];
+
+  const form = document.createElement('form');
+  form.id = 'form';
+  document.body.appendChild(form);
+
+  testData.forEach(data => {
+    form.removeAttribute('autocapitalize');
+
+    if (data.formValue !== null) {
+      form.setAttribute('autocapitalize', data.formValue);
+    }
+
+    formElements.forEach(elementData => {
+      const element = document.createElement(elementData.element);
+      form.appendChild(element);
+
+      const element2 = document.createElement(elementData.element);
+      element2.setAttribute('form', 'form');
+      document.body.appendChild(element2);
+
+      if (data.formElementValue !== null) {
+        element.setAttribute('autocapitalize', data.formElementValue);
+        element2.setAttribute('autocapitalize', data.formElementValue);
+      }
+
+      const descriptionSuffix = 'with "' + data.formValue
+          + '" and form element with "'+ data.formElementValue + '"';
+
+      if (elementData.inherits) {
+        assert_equals(element.autocapitalize, data.inheritedResult,
+                      `${elementData.element} element with form parent `
+                          + `${descriptionSuffix}`);
+        assert_equals(element2.autocapitalize, data.inheritedResult,
+                      `${elementData.element} element with form owner attribute`
+                          + ` set ${descriptionSuffix}`);
+      } else {
+        assert_equals(element.autocapitalize, data.uninheritedResult,
+                      `${elementData.element} element with form parent `
+                          + `${descriptionSuffix}`);
+        assert_equals(element2.autocapitalize, data.uninheritedResult,
+                      `${elementData.element} element with form owner attribute`
+                          + `set ${descriptionSuffix}`);
+      }
+    });
+  });
+}, "Test inheriting values from a form.")
+
+test(function() {
+  const testData = [ 'text',
+                     'search',
+                     'email',
+                     'url',
+                     'tel',
+                     'number',
+                     'date',
+                     'color',
+                     'password' ];
+
+  testData.forEach(function(data) {
+    const form = document.createElement('form');
+    form.setAttribute('autocapitalize', 'sentences');
+    const input = document.createElement('input');
+    input.setAttribute('type', data);
+    form.appendChild(input);
+
+    assert_equals(input.autocapitalize, 'sentences');
+  });
+}, "Verify that even input types that are never autocapitalized support the "
++ "IDL interface.")
+
+</script>
+</body>
+</html>