💎 PREMIUM: TR/html/dom.html - Complete Album!

HTML

Living Standard — Last Updated 17 December 2025

1. 3 Semantics, structure, and APIs of HTML documents
   1. 3.1 Documents
      1. 3.1.1 The Document object
      2. 3.1.2 The DocumentOrShadowRoot interface
      3. 3.1.3 Resource metadata management
      4. 3.1.4 Reporting document loading status
      5. 3.1.5 Render-blocking mechanism
      6. 3.1.6 DOM tree accessors
   2. 3.2 Elements
      1. 3.2.1 Semantics
      2. 3.2.2 Elements in the DOM
      3. 3.2.3 HTML element constructors
      4. 3.2.4 Element definitions
         1. 3.2.4.1 Attributes
      5. 3.2.5 Content models
         1. 3.2.5.1 The "nothing" content model
         2. 3.2.5.2 Kinds of content
            1. 3.2.5.2.1 Metadata content
            2. 3.2.5.2.2 Flow content
            3. 3.2.5.2.3 Sectioning content
            4. 3.2.5.2.4 Heading content
            5. 3.2.5.2.5 Phrasing content
            6. 3.2.5.2.6 Embedded content
            7. 3.2.5.2.7 Interactive content
            8. 3.2.5.2.8 Palpable content
            9. 3.2.5.2.9 Script-supporting elements
            10. 3.2.5.2.10 select element inner content elements
            11. 3.2.5.2.11 optgroup element inner content elements
            12. 3.2.5.2.12 option element inner content elements
         3. 3.2.5.3 Transparent content models
         4. 3.2.5.4 Paragraphs
      6. 3.2.6 Global attributes
         1. 3.2.6.1 The title attribute
         2. 3.2.6.2 The lang and xml:lang attributes
         3. 3.2.6.3 The translate attribute
         4. 3.2.6.4 The dir attribute
         5. 3.2.6.5 The style attribute
         6. 3.2.6.6 Embedding custom non-visible data with the data-* attributes
      7. 3.2.7 The innerText and outerText properties
      8. 3.2.8 Requirements relating to the bidirectional algorithm
         1. 3.2.8.1 Authoring conformance criteria for bidirectional-algorithm formatting characters
         2. 3.2.8.2 User agent conformance criteria
      9. 3.2.9 Requirements related to ARIA and to platform accessibility APIs

3 Semantics, structure, and APIs of HTML documents

3.1 Documents

Every XML and HTML document in an HTML UA is represented by a Document object. [DOM]

The Document object's URL is defined in DOM. It is initially set when the Document object is created, but can change during the lifetime of the Document object; for example, it changes when the user navigates to a fragment on the page and when the pushState() method is called with a new URL. [DOM]

Interactive user agents typically expose the Document object's URL in their user interface. This is the primary mechanism by which a user can tell if a site is attempting to impersonate another.

The Document object's origin is defined in DOM. It is initially set when the Document object is created, and can change during the lifetime of the Document only upon setting document.domain. A Document's origin can differ from the origin of its URL; for example when a child navigable is created, its active document's origin is inherited from its parent's active document's origin, even though its active document's URL is about:blank. [DOM]

When a Document is created by a script using the createDocument() or createHTMLDocument() methods, the Document is ready for post-load tasks immediately.

The document's referrer is a string (representing a URL) that can be set when the Document is created. If it is not explicitly set, then its value is the empty string.

3.1.1 The Document object

DOM defines a Document interface, which this specification extends significantly.

enum DocumentReadyState { "loading", "interactive", "complete" };
enum DocumentVisibilityState { "visible", "hidden" };
typedef (HTMLScriptElement or SVGScriptElement) HTMLOrSVGScriptElement;

[LegacyOverrideBuiltIns]
partial interface Document {
  static Document parseHTMLUnsafe((TrustedHTML or DOMString) html);

  // resource metadata management
  [PutForwards=href, LegacyUnforgeable] readonly attribute Location? location;
  attribute USVString domain;
  readonly attribute USVString referrer;
  attribute USVString cookie;
  readonly attribute DOMString lastModified;
  readonly attribute DocumentReadyState readyState;

  // DOM tree accessors
  getter object (DOMString name);
  [CEReactions] attribute DOMString title;
  [CEReactions] attribute DOMString dir;
  [CEReactions] attribute HTMLElement? body;
  readonly attribute HTMLHeadElement? head;
  [SameObject] readonly attribute HTMLCollection images;
  [SameObject] readonly attribute HTMLCollection embeds;
  [SameObject] readonly attribute HTMLCollection plugins;
  [SameObject] readonly attribute HTMLCollection links;
  [SameObject] readonly attribute HTMLCollection forms;
  [SameObject] readonly attribute HTMLCollection scripts;
  NodeList getElementsByName(DOMString elementName);
  readonly attribute HTMLOrSVGScriptElement? currentScript; // classic scripts in a document tree only

  // dynamic markup insertion
  [CEReactions] Document open(optional DOMString unused1, optional DOMString unused2); // both arguments are ignored
  WindowProxy? open(USVString url, DOMString name, DOMString features);
  [CEReactions] undefined close();
  [CEReactions] undefined write((TrustedHTML or DOMString)... text);
  [CEReactions] undefined writeln((TrustedHTML or DOMString)... text);

  // user interaction
  readonly attribute WindowProxy? defaultView;
  boolean hasFocus();
  [CEReactions] attribute DOMString designMode;
  [CEReactions] boolean execCommand(DOMString commandId, optional boolean showUI = false, optional DOMString value = "");
  boolean queryCommandEnabled(DOMString commandId);
  boolean queryCommandIndeterm(DOMString commandId);
  boolean queryCommandState(DOMString commandId);
  boolean queryCommandSupported(DOMString commandId);
  DOMString queryCommandValue(DOMString commandId);
  readonly attribute boolean hidden;
  readonly attribute DocumentVisibilityState visibilityState;

  // special event handler IDL attributes that only apply to Document objects
  [LegacyLenientThis] attribute EventHandler onreadystatechange;
  attribute EventHandler onvisibilitychange;

  // also has obsolete members
};
Document includes GlobalEventHandlers;

Each Document has a policy container (a policy container), initially a new policy container, which contains policies which apply to the Document.

Each Document has a permissions policy, which is a permissions policy, which is initially empty.

Each Document has a module map, which is a module map, initially empty.

Each Document has an opener policy, which is an opener policy, initially a new opener policy.

Each Document has an is initial about:blank, which is a boolean, initially false.

Each Document has a during-loading navigation ID for WebDriver BiDi, which is a navigation ID or null, initially null.

As the name indicates, this is used for interfacing with the WebDriver BiDi specification, which needs to be informed about certain occurrences during the early parts of the Document's lifecycle, in a way that ties them to the original navigation ID used when the navigation that created this Document was the ongoing navigation. This eventually gets set back to null, after WebDriver BiDi considers the loading process to be finished. [BIDI]

Each Document has an about base URL, which is a URL or null, initially null.

This is only populated for "about:"-schemed Documents.

Each Document has a bfcache blocking details, which is a set of not restored reason details, initially empty.

Each Document has an open dialogs list, which is a list of dialog elements, initially empty.

3.1.2 The DocumentOrShadowRoot interface

DOM defines the DocumentOrShadowRoot mixin, which this specification extends.

partial interface mixin DocumentOrShadowRoot {
  readonly attribute Element? activeElement;
};

3.1.3 Resource metadata management

document.referrer

✔MDN

Document/referrer

Support in all current engines.

Firefox1+Safari1+Chrome1+

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Opera3+Edge79+

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Edge (Legacy)12+Internet Explorer4+

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Firefox Android?Safari iOS?Chrome Android?WebView Android?Samsung Internet?Opera Android10.1+

Returns the URL of the Document from which the user navigated to this one, unless it was blocked or there was no such document, in which case it returns the empty string.

The noreferrer link type can be used to block the referrer.

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document.cookie [ = value ]

Returns the HTTP cookies that apply to the Document. If there are no cookies or cookies can't be applied to this resource, the empty string will be returned.

Can be set, to add a new cookie to the element's set of HTTP cookies.

If the contents are sandboxed into an opaque origin (e.g., in an iframe with the sandbox attribute), a "SecurityError" DOMException will be thrown on getting and setting.

The cookie attribute represents the cookies of the resource identified by the document's URL.

Using the synchronous document.cookie API can be a source of performance issues. The Cookie Store API can be used instead, as it provides an asynchronous way to handle cookies to avoid performance issues. See the Cookie Store API introduction for more information. [COOKIESTORE]

Since the cookie attribute is accessible across frames, the path restrictions on cookies are only a tool to help manage which cookies are sent to which parts of the site, and are not in any way a security feature.

The cookie attribute's getter and setter synchronously access shared state. Since there is no locking mechanism, other browsing contexts in a multiprocess user agent can modify cookies while scripts are running. A site could, for instance, try to read a cookie, increment its value, then write it back out, using the new value of the cookie as a unique identifier for the session; if the site does this twice in two different browser windows at the same time, it might end up using the same "unique" identifier for both sessions, with potentially disastrous effects.

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document.lastModified

✔MDN

Document/lastModified

Support in all current engines.

Firefox1+Safari1+Chrome1+

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Opera12.1+Edge79+

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Edge (Legacy)12+Internet Explorer4+

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Firefox Android?Safari iOS?Chrome Android?WebView Android?Samsung Internet?Opera Android12.1+

Returns the date of the last modification to the document, as reported by the server, in the form "MM/DD/YYYY hh:mm:ss", in the user's local time zone.

If the last modification date is not known, the current time is returned instead.

The Document's source file's last modification date and time must be derived from relevant features of the networking protocols used, e.g. from the value of the HTTP `Last-Modified` header of the document, or from metadata in the file system for local files. If the last modification date and time are not known, the attribute must return the current date and time in the above format.

3.1.4 Reporting document loading status

document.readyState

Returns "loading" while the Document is loading, "interactive" once it is finished parsing but still loading subresources, and "complete" once it has loaded.

The readystatechange event fires on the Document object when this value changes.

The DOMContentLoaded event fires after the transition to "interactive" but before the transition to "complete", at the point where all subresources apart from async script elements have loaded.

Each Document has a current document readiness, a string, initially "complete".

For Document objects created via the create and initialize a Document object algorithm, this will be immediately reset to "loading" before any script can observe the value of document.readyState. This default applies to other cases such as initial about:blank Documents or Documents without a browsing context.

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