Document

Document 介面代表所有在瀏覽器中載入的網頁，也是作為網頁內容 DOM 樹（包含如 <body> (en-US)、<table> 與其它的元素）的進入點。Document 提供了網頁文件所需的通用函式，例如取得頁面 URL 或是建立網頁文件中新的元素節點等。

Document 介面描述了各種類型文件的共同屬性與方法。根據文件的類型（如 HTML、XML (en-US)、SVG 等），也會擁有各自的 API：HTML 文件（content type 為 text/html）實作了 HTMLDocument 介面，而 XML 及 SVG 文件實作了 XMLDocument (en-US) 介面。

請注意 window.document 物件為 HTMLDocument 所建構。

屬性

這個介面繼承了 Node 以及 EventTarget 介面。

Document.all (en-US) Deprecated Non-Standard: Provides access to all elements with an id. This is a legacy, non-standard interface and you should use the document.getElementById() (en-US) method instead.
Document.async (en-US) Deprecated: Used with Document.load to indicate an asynchronous request.
Document.characterSet (en-US) Read only: Returns the character set being used by the document.
Document.charset (en-US) Read only Deprecated: Alias of Document.characterSet (en-US). Use this property instead.
Document.compatMode (en-US) Read only Experimental: Indicates whether the document is rendered in quirks or strict mode.
Document.contentType (en-US) Read only Experimental: Returns the Content-Type from the MIME Header of the current document.
Document.doctype (en-US) Read only: 回傳目前文件的 Document Type Definition（DTD）。
Document.documentElement Read only: 回傳當前文件 Document 的根元素。以 HTML documents為例：它會回傳 <html> (en-US) 這項元素。
Document.documentURI (en-US) Read only: Returns the document location as a string.
Document.domConfig (en-US) Deprecated: Should return a DOMConfiguration object.
Document.fullscreen (en-US): true when the document is in full-screen mode.
Document.hidden (en-US) Read only: …
Document.implementation (en-US) Read only: Returns the DOM implementation associated with the current document.
Document.inputEncoding (en-US) Read only Deprecated: Alias of Document.characterSet (en-US). Use this property instead.
Document.lastStyleSheetSet (en-US) Read only: Returns the name of the style sheet set that was last enabled. Has the value null until the style sheet is changed by setting the value of selectedStyleSheetSet (en-US).
Document.mozSyntheticDocument (en-US) Non-Standard: Returns a Boolean that is true only if this document is synthetic, such as a standalone image, video, audio file, or the like.
Document.mozFullScreenElement (en-US) Read only Non-Standard: The element that's currently in full screen mode for this document.
Document.mozFullScreenEnabled (en-US) Read only Non-Standard: true if calling Element.mozRequestFullscreen() (en-US) would succeed in the curent document.
Document.pointerLockElement (en-US) Read only Experimental: Returns the element set as the target for mouse events while the pointer is locked. null if lock is pending, pointer is unlocked, or if the target is in another document.
Document.preferredStyleSheetSet (en-US) Read only: Returns the preferred style sheet set as specified by the page author.
Document.scrollingElement (en-US) Experimental Read only: Returns a reference to the Element that scrolls the document.
Document.selectedStyleSheetSet (en-US): Returns which style sheet set is currently in use.
Document.styleSheets (en-US) Read only: Returns a list of the style sheet objects on the current document.
Document.styleSheetSets (en-US) Read only: Returns a list of the style sheet sets available on the document.
Document.timeline (en-US) Read only: …
Document.undoManager Read only Experimental: …
Document.visibilityState (en-US) Read only: Returns a string denoting the visibility state of the document. Possible values are visible, hidden, prerender, and unloaded.
Document.xmlEncoding (en-US) Deprecated: Returns the encoding as determined by the XML declaration.
Document.xmlStandalone 已過時 Gecko 10.0: Returns true if the XML declaration specifies the document to be standalone (e.g., An external part of the DTD affects the document's content), else false.
Document.xmlVersion (en-US) 已過時 Gecko 10.0: Returns the version number as specified in the XML declaration or "1.0" if the declaration is absent.

The Document interface is extended with the ParentNode interface:

HTML 文件擴充

window.document 物件的部分屬性繼承自 HTML 文件的 HTMLDocument 介面，或是來自 Document 從 HTML5 之後擴充的屬性。

Document.activeElement (en-US) Read only: Returns the currently focused element.
Document.alinkColor (en-US) Deprecated: Returns or sets the color of active links in the document body.
Document.anchors (en-US): Returns a list of all of the anchors in the document.
Document.applets (en-US) Deprecated: Returns an ordered list of the applets within a document.
Document.bgColor (en-US) Deprecated: Gets/sets the background color of the current document.
Document.body: Returns the <body> (en-US) element of the current document.
Document.cookie (en-US): Returns a semicolon-separated list of the cookies for that document or sets a single cookie.
Document.defaultView Read only: Returns a reference to the window object.
Document.designMode: Gets/sets the ability to edit the whole document.
Document.dir (en-US) Read only: Gets/sets directionality (rtl/ltr) of the document.
Document.domain (en-US) Read only: Returns the domain of the current document.
Document.embeds (en-US) Read only: Returns a list of the embedded <embed> (en-US) elements within the current document.
document.fgColor (en-US) Deprecated: Gets/sets the foreground color, or text color, of the current document.
Document.forms Read only: Returns a list of the <form> elements within the current document.
Document.head Read only: Returns the <head> (en-US) element of the current document.
Document.height (en-US) Non-Standard: Gets/sets the height of the current document.
Document.images (en-US) Read only: Returns a list of the images in the current document.
Document.lastModified (en-US) Read only: Returns the date on which the document was last modified.
Document.linkColor (en-US) Deprecated: Gets/sets the color of hyperlinks in the document.
Document.links (en-US) Read only: Returns a list of all the hyperlinks in the document.
Document.location (en-US) Read only: Returns the URI of the current document.
Document.plugins (en-US) Read only: Returns a list of the available plugins.
Document.readyState Read only: Returns loading status of the document.
Document.referrer (en-US) Read only: Returns the URI of the page that linked to this page.
Document.scripts (en-US) Read only: Returns all the <script> elements on the document.
Document.title (en-US): Sets or gets title of the current document.
Document.URL (en-US) Read only: Returns the document location as a string.
Document.vlinkColor (en-US) Deprecated: Gets/sets the color of visited hyperlinks.
Document.width Non-Standard: Returns the width of the current document.

事件處理器

Document.onafterscriptexecute (en-US) Non-Standard: Represents the event handling code for the afterscriptexecute (en-US) event.
Document.onbeforescriptexecute (en-US) Non-Standard: Represents the event handling code for the beforescriptexecute (en-US) event.
Document.oncopy Non-Standard: Represents the event handling code for the copy (en-US) event.
Document.oncut Non-Standard: Represents the event handling code for the cut (en-US) event.
Document.onfullscreenchange (en-US): Is an event handler representing the code to be called when the fullscreenchange (en-US) event is raised.
Document.onfullscreenerror (en-US): Is an event handler representing the code to be called when the fullscreenerror (en-US) event is raised.
Document.onpaste Non-Standard: Represents the event handling code for the paste (en-US) event.
Document.onpointerlockchange Experimental: Represents the event handling code for the pointerlockchange (en-US) event.
Document.onpointerlockerror Experimental: Represetnts the event handling code for the pointerlockerror (en-US) event.
Document.onreadystatechange: Represents the event handling code for the readystatechange (en-US) event.
Document.onselectionchange (en-US) Experimental: Is an event handler representing the code to be called when the selectionchange event is raised.
Document.onwheel Non-Standard: Represents the event handling code for the wheel (en-US) event.

此介面繼承了 GlobalEventHandlers 的事件處理器：

This interface doesn't include any properties except for the event handlers listed below.

事件處理器

These event handlers are defined on the GlobalEventHandlers mixin, and implemented by HTMLElement, Document, Window, as well as by WorkerGlobalScope (en-US) for Web Workers.

GlobalEventHandlers.onabort (en-US): Is an event handler representing the code to be called when the abort (en-US) event is raised.
GlobalEventHandlers.onanimationcancel (en-US) Non-Standard: An event handler called when an animationcancel event is sent, indicating that a running CSS animation has been canceled.
GlobalEventHandlers.onanimationend (en-US) Non-Standard: An event handler called when an animationend (en-US) event is sent, indicating that a CSS animation has stopped playing.
GlobalEventHandlers.onanimationiteration (en-US) Non-Standard: An event handler called when an animationiteration (en-US) event has been sent, indicating that a CSS animation has begun playing a new iteration of the animation sequence.
GlobalEventHandlers.onanimationstart (en-US) Non-Standard: An event handler called when an animationstart (en-US) event is sent, indicating that a CSS animation has started playing.
GlobalEventHandlers.onauxclick (en-US) Non-Standard: An event handler called when an auxclick event is sent, indicating that a non-primary button has been pressed on an input device (e.g. a middle mouse button).
GlobalEventHandlers.onblur (en-US): Is an event handler representing the code to be called when the blur (en-US) event is raised.
GlobalEventHandlers.onerror (en-US): Is an OnErrorEventHandler representing the code to be called when the error (en-US) event is raised.
GlobalEventHandlers.onfocus (en-US): Is an event handler representing the code to be called when the focus (en-US) event is raised.
GlobalEventHandlers.oncancel (en-US): Is an event handler representing the code to be called when the cancel event is raised.
GlobalEventHandlers.oncanplay (en-US): Is an event handler representing the code to be called when the canplay (en-US) event is raised.
GlobalEventHandlers.oncanplaythrough (en-US): Is an event handler representing the code to be called when the canplaythrough (en-US) event is raised.
GlobalEventHandlers.onchange (en-US): Is an event handler representing the code to be called when the change (en-US) event is raised.
GlobalEventHandlers.onclick: Is an event handler representing the code to be called when the click event is raised.
GlobalEventHandlers.onclose: Is an event handler representing the code to be called when the close event is raised.
GlobalEventHandlers.oncontextmenu (en-US): Is an event handler representing the code to be called when the contextmenu (en-US) event is raised.
GlobalEventHandlers.oncuechange (en-US): Is an event handler representing the code to be called when the cuechange (en-US) event is raised.
GlobalEventHandlers.ondblclick (en-US): Is an event handler representing the code to be called when the dblclick (en-US) event is raised.
GlobalEventHandlers.ondrag (en-US): Is an event handler representing the code to be called when the drag (en-US) event is raised.
GlobalEventHandlers.ondragend (en-US): Is an event handler representing the code to be called when the dragend (en-US) event is raised.
GlobalEventHandlers.ondragenter (en-US): Is an event handler representing the code to be called when the dragenter (en-US) event is raised.
GlobalEventHandlers.ondragexit (en-US): Is an event handler representing the code to be called when the dragexit event is raised.
GlobalEventHandlers.ondragleave (en-US): Is an event handler representing the code to be called when the dragleave (en-US) event is raised.
GlobalEventHandlers.ondragover (en-US): Is an event handler representing the code to be called when the dragover (en-US) event is raised.
GlobalEventHandlers.ondragstart (en-US): Is an event handler representing the code to be called when the dragstart (en-US) event is raised.
GlobalEventHandlers.ondrop (en-US): Is an event handler representing the code to be called when the drop (en-US) event is raised.
GlobalEventHandlers.ondurationchange (en-US): Is an event handler representing the code to be called when the durationchange (en-US) event is raised.
GlobalEventHandlers.onemptied (en-US): Is an event handler representing the code to be called when the emptied (en-US) event is raised.
GlobalEventHandlers.onended (en-US): Is an event handler representing the code to be called when the ended (en-US) event is raised.
GlobalEventHandlers.ongotpointercapture (en-US): Is an event handler representing the code to be called when the gotpointercapture event type is raised.
GlobalEventHandlers.oninput (en-US): Is an event handler representing the code to be called when the input (en-US) event is raised.
GlobalEventHandlers.oninvalid (en-US): Is an event handler representing the code to be called when the invalid (en-US) event is raised.
GlobalEventHandlers.onkeydown (en-US): Is an event handler representing the code to be called when the keydown (en-US) event is raised.
GlobalEventHandlers.onkeypress (en-US): Is an event handler representing the code to be called when the keypress (en-US) event is raised.
GlobalEventHandlers.onkeyup (en-US): Is an event handler representing the code to be called when the keyup (en-US) event is raised.
GlobalEventHandlers.onload (en-US): Is an event handler representing the code to be called when the load (en-US) event is raised.
GlobalEventHandlers.onloadeddata (en-US): Is an event handler representing the code to be called when the loadeddata (en-US) event is raised.
GlobalEventHandlers.onloadedmetadata (en-US): Is an event handler representing the code to be called when the loadedmetadata (en-US) event is raised.
GlobalEventHandlers.onloadend (en-US): Is an event handler representing the code to be called when the loadend (en-US) event is raised (when progress has stopped on the loading of a resource.)
GlobalEventHandlers.onloadstart (en-US): Is an event handler representing the code to be called when the loadstart (en-US) event is raised (when progress has begun on the loading of a resource.)
GlobalEventHandlers.onlostpointercapture (en-US): Is an event handler representing the code to be called when the lostpointercapture event type is raised.
GlobalEventHandlers.onmousedown (en-US): Is an event handler representing the code to be called when the mousedown (en-US) event is raised.
GlobalEventHandlers.onmouseenter (en-US): Is an event handler representing the code to be called when the mouseenter (en-US) event is raised.
GlobalEventHandlers.onmouseleave (en-US): Is an event handler representing the code to be called when the mouseleave (en-US) event is raised.
GlobalEventHandlers.onmousemove (en-US): Is an event handler representing the code to be called when the mousemove (en-US) event is raised.
GlobalEventHandlers.onmouseout (en-US): Is an event handler representing the code to be called when the mouseout (en-US) event is raised.
GlobalEventHandlers.onmouseover (en-US): Is an event handler representing the code to be called when the mouseover (en-US) event is raised.
GlobalEventHandlers.onmouseup (en-US): Is an event handler representing the code to be called when the mouseup (en-US) event is raised.
GlobalEventHandlers.onmousewheel (en-US): Is an event handler representing the code to be called when the mousewheel (en-US) event is raised.
GlobalEventHandlers.onpause (en-US): Is an event handler representing the code to be called when the pause (en-US) event is raised.
GlobalEventHandlers.onplay (en-US): Is an event handler representing the code to be called when the play (en-US) event is raised.
GlobalEventHandlers.onplaying (en-US): Is an event handler representing the code to be called when the playing (en-US) event is raised.
GlobalEventHandlers.onpointerdown (en-US): Is an event handler representing the code to be called when the pointerdown event is raised.
GlobalEventHandlers.onpointermove (en-US): Is an event handler representing the code to be called when the pointermove event is raised.
GlobalEventHandlers.onpointerup (en-US): Is an event handler representing the code to be called when the pointerup event is raised.
GlobalEventHandlers.onpointercancel (en-US): Is an event handler representing the code to be called when the pointercancel event is raised.
GlobalEventHandlers.onpointerover (en-US): Is an event handler representing the code to be called when the pointerover event is raised.
GlobalEventHandlers.onpointerout (en-US): Is an event handler representing the code to be called when the pointerout event is raised.
GlobalEventHandlers.onpointerenter (en-US): Is an event handler representing the code to be called when the pointerevent event is raised.
GlobalEventHandlers.onpointerleave (en-US): Is an event handler representing the code to be called when the pointerleave event is raised.
GlobalEventHandlers.onpointerlockchange Experimental: Is an event handler representing the code to be called when the pointerlockchange (en-US) event is raised.
GlobalEventHandlers.onpointerlockerror Experimental: Is an event handler representing the code to be called when the pointerlockerror (en-US) event is raised.
GlobalEventHandlers.onprogress: Is an event handler representing the code to be called when the progress (en-US) event is raised.
GlobalEventHandlers.onratechange: Is an event handler representing the code to be called when the ratechange (en-US) event is raised.
GlobalEventHandlers.onreset (en-US): Is an event handler representing the code to be called when the reset (en-US) event is raised.
GlobalEventHandlers.onscroll (en-US): Is an event handler representing the code to be called when the scroll (en-US) event is raised.
GlobalEventHandlers.onseeked: Is an event handler representing the code to be called when the seeked (en-US) event is raised.
GlobalEventHandlers.onseeking: Is an event handler representing the code to be called when the seeking (en-US) event is raised.
GlobalEventHandlers.onselect (en-US): Is an event handler representing the code to be called when the select (en-US) event is raised.
GlobalEventHandlers.onselectstart (en-US): Is an event handler representing the code to be called when the selectionchange event is raised, i.e. when the user starts to make a new text selection on a web page.
GlobalEventHandlers.onselectionchange (en-US): Is an event handler representing the code to be called when the selectionchange event is raised, i.e. when the text selected on a web page changes.
GlobalEventHandlers.onshow: Is an event handler representing the code to be called when the show (en-US) event is raised.
GlobalEventHandlers.onsort Experimental: Is an event handler representing the code to be called when the sort event is raised.
GlobalEventHandlers.onstalled: Is an event handler representing the code to be called when the stalled (en-US) event is raised.
GlobalEventHandlers.onsubmit (en-US): Is an event handler representing the code to be called when the submit event is raised.
GlobalEventHandlers.onsuspend: Is an event handler representing the code to be called when the suspend (en-US) event is raised.
GlobalEventHandlers.ontimeupdate: Is an event handler representing the code to be called when the timeupdate (en-US) event is raised.
GlobalEventHandlers.onvolumechange: Is an event handler representing the code to be called when the volumechange (en-US) event is raised.
GlobalEventHandlers.ontouchcancel (en-US): Is an event handler representing the code to be called when the touchcancel event is raised.
GlobalEventHandlers.ontouchend (en-US): Is an event handler representing the code to be called when the touchend (en-US) event is raised.
GlobalEventHandlers.ontouchmove (en-US): Is an event handler representing the code to be called when the touchmove (en-US) event is raised.
GlobalEventHandlers.ontouchstart (en-US): Is an event handler representing the code to be called when the touchstart (en-US) event is raised.
GlobalEventHandlers.ontransitioncancel (en-US): An event handler called when a transitioncancel event is sent, indicating that a CSS transition has been cancelled.
GlobalEventHandlers.ontransitionend (en-US): An event handler called when a transitionend (en-US) event is sent, indicating that a CSS transition has finished playing.
GlobalEventHandlers.onwaiting: Is an event handler representing the code to be called when the waiting (en-US) event is raised.

方法

This interface also inherits from the Node and EventTarget interfaces.

Document.adoptNode() (en-US): Adopt node from an external document.
Document.captureEvents() Deprecated: See Window.captureEvents (en-US).
Document.caretPositionFromPoint() (en-US) Experimental: Gets the CaretPosition (en-US) at or near the specified coordinates.
Document.caretRangeFromPoint() (en-US) Non-Standard: Gets a Range object for the document fragment under the specified coordinates.
Document.createAttribute() (en-US): Creates a new Attr (en-US) object and returns it.
Document.createAttributeNS() (en-US): Creates a new attribute node in a given namespace and returns it.
Document.createCDATASection() (en-US): Creates a new CDATA node and returns it.
Document.createComment() (en-US): Creates a new comment node and returns it.
Document.createDocumentFragment(): Creates a new document fragment.
Document.createElement(): Creates a new element with the given tag name.
Document.createElementNS() (en-US): Creates a new element with the given tag name and namespace URI.
Document.createEntityReference() (en-US): Creates a new entity reference object and returns it.
Document.createEvent(): Creates an event object.
Document.createNodeIterator() (en-US): Creates a NodeIterator (en-US) object.
Document.createProcessingInstruction() (en-US): Creates a new ProcessingInstruction (en-US) object.
Document.createRange(): Creates a Range object.
Document.createTextNode(): Creates a text node.
Document.createTouch() (en-US): Creates a Touch object.
Document.createTouchList() (en-US): Creates a TouchList object.
Document.createTreeWalker(): Creates a TreeWalker (en-US) object.
Document.elementFromPoint() (en-US) Experimental: Returns the topmost element at the specified coordinates.
Document.elementsFromPoint() (en-US) Experimental: Returns an array of all elements at the specified coordinates.
Document.enableStyleSheetsForSet() (en-US): Enables the style sheets for the specified style sheet set.
Document.exitPointerLock() (en-US) Experimental: Release the pointer lock.
Document.getAnimations() (en-US) Experimental: Returns an array of all Animation (en-US) objects currently in effect, whose target elements are descendants of the document.
Document.getElementsByClassName(): Returns a list of elements with the given class name.
Document.getElementsByTagName() (en-US): Returns a list of elements with the given tag name.
Document.getElementsByTagNameNS() (en-US): Returns a list of elements with the given tag name and namespace.
Document.importNode() (en-US): Returns a clone of a node from an external document.
Document.normalizeDocument(): Replaces entities, normalizes text nodes, etc.
Document.registerElement() Experimental: Registers a web component.
Document.releaseCapture() (en-US) Non-Standard: Releases the current mouse capture if it's on an element in this document.
Document.releaseEvents() Non-Standard Deprecated: See Window.releaseEvents() (en-US).
Document.routeEvent() Non-Standard 已過時 Gecko 24: See Window.routeEvent().
Document.mozSetImageElement() (en-US) Non-Standard: Allows you to change the element being used as the background image for a specified element ID.

The Document interface is extended with the ParentNode interface:

document.getElementById(String id) (en-US): Returns an object reference to the identified element.
document.querySelector(String selector): Returns the first Element node within the document, in document order, that matches the specified selectors.
document.querySelectorAll(String selector) (en-US): Returns a list of all the Element nodes within the document that match the specified selectors.

The Document interface is extended with the XPathEvaluator (en-US) interface:

document.createExpression(String expression, XPathNSResolver resolver) (en-US): Compiles an XPathExpression which can then be used for (repeated) evaluations.
document.createNSResolver(Node resolver) (en-US): Creates an XPathNSResolver (en-US) object.
document.evaluate(String expression, Node contextNode, XPathNSResolver resolver, Number type, Object result) (en-US): Evaluates an XPath expression.

HTML 文件擴充

Document 物件的部分方法繼承自 HTML 文件的 HTMLDocument 介面，或是來自 Document 從 HTML5 之後擴充的方法：

document.clear() (en-US) Non-Standard Deprecated: In majority of modern browsers, including recent versions of Firefox and Internet Explorer, this method does nothing.
document.close() (en-US): Closes a document stream for writing.
document.execCommand(String command[, Boolean showUI[, String value]]): On an editable document, executes a formating command.
document.getElementsByName(String name) (en-US): Returns a list of elements with the given name.
document.getSelection() (en-US): Returns a Selection (en-US) object related to text selected in the document.
document.hasFocus() (en-US): Returns true if the focus is currently located anywhere inside the specified document.
document.open() (en-US): Opens a document stream for writing.
document.queryCommandEnabled(String command) (en-US): Returns true if the formating command can be executed on the current range.
document.queryCommandIndeterm(String command): Returns true if the formating command is in an indeterminate state on the current range.
document.queryCommandState(String command) (en-US): Returns true if the formating command has been executed on the current range.
document.queryCommandSupported(String command) (en-US): Returns true if the formating command is supported on the current range.
document.queryCommandValue(String command): Returns the current value of the current range for a formating command.
document.write(String text) (en-US): Writes text in a document.
document.writeln(String text) (en-US): Writes a line of text in a document.

規範

Specification
DOM Standard # interface-document
HTML Standard # the-document-object
CSSOM View Module # extensions-to-the-document-interface
Pointer Lock 2.0 # extensions-to-the-document-interface
Selection API # extensions-to-document-interface

瀏覽器相容性備註

Firefox notes

Mozilla defines a set of non-standard properties made only for XUL content:

document.currentScript (en-US) Non-Standard: Returns the <script> element that is currently executing.
document.documentURIObject: (Mozilla add-ons only!) Returns the nsIURI object representing the URI of the document. This property only has special meaning in privileged JavaScript code (with UniversalXPConnect privileges).
document.popupNode: Returns the node upon which a popup was invoked.
document.tooltipNode: Returns the node which is the target of the current tooltip.

Mozilla also define some non-standard methods:

document.execCommandShowHelp 已過時 Gecko 14.0: This method never did anything and always threw an exception, so it was removed in Gecko 14.0 (Firefox 14.0 / Thunderbird 14.0 / SeaMonkey 2.11).
document.getBoxObjectFor (en-US): Use the Element.getBoundingClientRect() (en-US) method instead.
document.loadOverlay: Loads a XUL overlay dynamically. This only works in XUL documents.
document.queryCommandText 已過時 Gecko 14.0: This method never did anything but throw an exception, and was removed in Gecko 14.0 (Firefox 14.0 / Thunderbird 14.0 / SeaMonkey 2.11).

Internet Explorer notes

Microsoft defines some non-standard properties:

document.fileSize* Non-Standard: Returns size in bytes of the document. Starting with Internet Explorer 11, that property is no longer supported. See MSDN.
Internet Explorer does not support all methods from the Node interface in the Document interface:

document.contains: As a work-around, document.body.contains() can be used.