Window

« DOM Reference

The window object represents a window containing a DOM document; the document property points to the DOM document loaded in that window. A window for a given document can be obtained using the document.defaultView property.

This section provides a brief reference for all of the methods, properties, and events available through the DOM window object. The window object implements the Window interface, which in turn inherits from the AbstractView interface. Some additional global functions, namespaces objects, interfaces, and constructors, not typically associated with the window, but available on it, are listed in the JavaScript Reference and DOM Reference.

In a tabbed browser, such as Firefox, each tab contains its own window object (and if you're writing an extension, the browser window itself is a separate window too - see Working with windows in chrome code for more information). That is, the window object is not shared between tabs in the same window. Some methods, namely window.resizeTo and window.resizeBy apply to the whole window and not to the specific tab the window object belongs to. Generally, anything that can't reasonably pertain to a tab pertains to the window instead.

Properties

Note that properties which are objects (e.g.,. for overriding the prototype of built-in elements) are listed in a separate section below.

Window.applicationCache
An OfflineResourceList object providing access to the offline resources for the window.
Window.closed
This property indicates whether the current window is closed or not.
Window.Components
The entry point to many XPCOM features. Some properties, e.g. classes, are only available to sufficiently privileged code. Web code should not use this property.
Window.console
Returns a reference to the console object providing access to the browser's debugging console.
Window.content and Window._content
Returns a reference to the content element in the current window. The obsolete variant with underscore is no longer available from Web content.
Window.controllers
Returns the XUL controller objects for the current chrome window.
Window.crypto
Returns the browser crypto object.
Window.defaultStatus Obsolete since Gecko 23
Gets/sets the status bar text for the given window.
Window.dialogArguments
Gets the arguments passed to the window (if it's a dialog box) at the time window.showModalDialog() was called. This is an nsIArray.
Window.directories
Synonym of window.personalbar
Window.document
Returns a reference to the document that the window contains.
Window.frameElement
Returns the element in which the window is embedded, or null if the window is not embedded.
Window.frames
Returns an array of the subframes in the current window.
Window.fullScreen
This property indicates whether the window is displayed in full screen or not.
window.globalStorage Obsolete since Gecko 13
Unsupported since Gecko 13 (Firefox 13). Use window.localStorage instead.
Was: Multiple storage objects that are used for storing data across multiple pages.
Window.history
Returns a reference to the history object.
Window.innerHeight
Gets the height of the content area of the browser window including, if rendered, the horizontal scrollbar.
window.innerWidth
Gets the width of the content area of the browser window including, if rendered, the vertical scrollbar.
Window.length
Returns the number of frames in the window. See also window.frames.
Window.location
Gets/sets the location, or current URL, of the window object.
Window.locationbar
Returns the locationbar object, whose visibility can be toggled in the window.
Window.localStorage
Returns a reference to the local storage object used to store data that may only be accessed by the origin that created it.
Window.menubar
Returns the menubar object, whose visibility can be toggled in the window.
Window.messageManager
Returns the message manager object for this window.
Window.mozAnimationStartTime
The time in milliseconds since epoch at which the current animation cycle began.
Window.mozInnerScreenX
Returns the horizontal (X) coordinate of the top-left corner of the window's viewport, in screen coordinates. This value is reported in CSS pixels. See mozScreenPixelsPerCSSPixel in nsIDOMWindowUtils for a conversion factor to adapt to screen pixels if needed.
Window.mozInnerScreenY
Returns the vertical (Y) coordinate of the top-left corner of the window's viewport, in screen coordinates. This value is reported in CSS pixels. See mozScreenPixelsPerCSSPixel for a conversion factor to adapt to screen pixels if needed.
Window.mozPaintCount
Returns the number of times the current document has been rendered to the screen in this window. This can be used to compute rendering performance.
Window.name
Gets/sets the name of the window.
Window.navigator
Returns a reference to the navigator object.
Window.opener
Returns a reference to the window that opened this current window.
Window.outerHeight
Gets the height of the outside of the browser window.
Window.outerWidth
Gets the width of the outside of the browser window.
Window.pageXOffset
An alias for window.scrollX.
Window.pageYOffset
An alias for window.scrollY
Window.parent
Returns a reference to the parent of the current window or subframe.
Window.performance
Provides a hosting area for performance related attributes.
Window.personalbar
Returns the personalbar object, whose visibility can be toggled in the window.
Window.pkcs11 Obsolete since Gecko 29
Formerly provided access to install and remove PKCS11 modules.
Window.returnValue
The return value to be returned to the function that called window.showModalDialog() to display the window as a modal dialog.
Window.screen
Returns a reference to the screen object associated with the window.
Window.screenX
Returns the horizontal distance of the left border of the user's browser from the left side of the screen.
Window.screenY
Returns the vertical distance of the top border of the user's browser from the top side of the screen.
Window.scrollbars
Returns the scrollbars object, whose visibility can be toggled in the window.
Window.scrollMaxX
The maximum offset that the window can be scrolled to horizontally.
(i.e., the document width minus the viewport width)
Window.scrollMaxY
The maximum offset that the window can be scrolled to vertically (i.e., the document height minus the viewport height).
Window.scrollX
Returns the number of pixels that the document has already been scrolled horizontally.
Window.scrollY
Returns the number of pixels that the document has already been scrolled vertically.
Window.self
Returns an object reference to the window object itself.
Window.sessionStorage
A storage object for storing data within a single page session.
Window.sidebar
Returns a reference to the window object of the sidebar.
Window.status
Gets/sets the text in the statusbar at the bottom of the browser.
Window.statusbar
Returns the statusbar object, whose visibility can be toggled in the window.
Window.toolbar
Returns the toolbar object, whose visibility can be toggled in the window.
Window.top
Returns a reference to the topmost window in the window hierarchy. This property is read only.
Window.window
Returns a reference to the current window.
window[0], window[1], etc.
Returns a reference to the window object in the frames. See Window.frames for more details.

Methods

EventTarget.addEventListener
Register an event handler to a specific event type on the window.
Window.alert
Displays an alert dialog.
Window.atob
Decodes a string of data which has been encoded using base-64 encoding.
Window.back
Moves back one in the window history.
Window.blur
Sets focus away from the window.
Window.btoa
Creates a base-64 encoded ASCII string from a string of binary data.
Window.captureEvents
Registers the window to capture all events of the specified type.
Window.clearImmediate
Cancels the repeated execution set using setImmediate.
Window.clearInterval
Cancels the repeated execution set using setInterval.
Window.clearTimeout
Cancels the repeated execution set using setTimeout.
Window.close
Closes the current window.
Window.confirm
Displays a dialog with a message that the user needs to respond to.
Window.disableExternalCapture Obsolete since Gecko 24
FIXME: NeedsContents
Window.dispatchEvent
Used to trigger an event.
Window.dump
Writes a message to the console.
Window.enableExternalCapture Obsolete since Gecko 24
FIXME: NeedsContents
Window.find
Searches for a given string in a window.
Window.focus
Sets focus on the current window.
Window.forward
Moves the window one document forward in the history.
Window.getAttention
Flashes the application icon.
Window.getAttentionWithCycleCount
FIXME: NeedsContents
Window.getComputedStyle
Gets computed style for the specified element. Computed style indicates the computed values of all CSS properties of the element.
Window.getDefaulComputedStyle
Gets default computed style for the specified element, ignoring author stylesheets.
Window.getSelection
Returns the selection object representing the selected item(s).
Window.home
Returns the browser to the home page.
Window.matchMedia
Returns a MediaQueryList object representing the specified media query string.
Window.maximize
FIXME: NeedsContents
Window.minimize (top-level XUL windows only)
Minimizes the window.
Window.moveBy
Moves the current window by a specified amount.
Window.moveTo
Moves the window to the specified coordinates.
Window.mozRequestAnimationFrame
Tells the browser that an animation is in progress, requesting that the browser schedule a repaint of the window for the next animation frame. This will cause a MozBeforePaint event to fire before that repaint occurs.
Window.open
Opens a new window.
Window.openDialog
Opens a new dialog window.
Window.postMessage
Provides a secure means for one window to send a string of data to another window, which need not be within the same domain as the first, in a secure manner.
Window.print
Opens the Print Dialog to print the current document.
Window.prompt
Returns the text entered by the user in a prompt dialog.
Window.releaseEvents
Releases the window from trapping events of a specific type.
Window.removeEventListener
Removes an event listener from the window.
Window.resizeBy
Resizes the current window by a certain amount.
Window.resizeTo
Dynamically resizes window.
Window.restore
FIXME: NeedsContents
Window.routeEvent Obsolete since Gecko 24
FIXME: NeedsContents
Window.scroll
Scrolls the window to a particular place in the document.
Window.scrollBy
Scrolls the document in the window by the given amount.
Window.scrollByLines
Scrolls the document by the given number of lines.
Window.scrollByPages
Scrolls the current document by the specified number of pages.
Window.scrollTo
Scrolls to a particular set of coordinates in the document.
Window.setCursor
Changes the cursor for the current window
Window.setImmediate
Execute a function after the browser has finished other heavy tasks
Window.setInterval
Execute a function each X milliseconds.
Window.setResizable
FIXME: NeedsContents
Window.setTimeout
Sets a delay for executing a function.
Window.showModalDialog
Displays a modal dialog.
Window.sizeToContent
Sizes the window according to its content.
Window.stop
This method stops window loading.
Window.updateCommands
Updates the state of commands of the current chrome window (UI).

Event handlers

These are properties of the window object that can be set to establish event handlers for the various things that can happen in the window that might be of interest.

Note: Starting in Gecko 9.0, you can now use the syntax if ("onabort" in window) to determine whether or not a given event handler property exists. This is because event handler interfaces have been updated to be proper web IDL interfaces. See DOM event handlers for details.

Window.onabort
An event handler property for abort events on the window.
Window.onbeforeunload
An event handler property for before-unload events on the window.
Window.onblur
An event handler property for blur events on the window.
Window.onchange
An event handler property for change events on the window.
Window.onclick
An event handler property for click events on the window.
Window.onclose
An event handler property for handling the window close event.
Window.oncontextmenu
An event handler property for right-click events on the window.
Window.ondevicelight
An event handler property for any ambient light levels changes
Window.ondevicemotion
FIXME: NeedsContents
Window.ondeviceorientation
An event handler property for any device orientation changes
Window.ondeviceproximity
An event handler property for device proximity event
Window.ondragdrop
An event handler property for drag and drop events on the window.
Window.onerror
An event handler property for errors raised on the window.
Window.onfocus
An event handler property for focus events on the window.
Window.onhashchange
An event handler property for hash change events on the window; called when the part of the URL after the hash mark ("#") changes.
Window.onkeydown
An event handler property for keydown events on the window.
Window.onkeypress
An event handler property for keypress events on the window.
Window.onkeyup
An event handler property for keyup events on the window.
Window.onload
An event handler property for window loading.
Window.onmousedown
An event handler property for mousedown events on the window.
Window.onmousemove
An event handler property for mousemove events on the window.
Window.onmouseout
An event handler property for mouseout events on the window.
Window.onmouseover
An event handler property for mouseover events on the window.
Window.onmouseup
An event handler property for mouseup events on the window.
Window.onmozbeforepaint
An event handler property for the MozBeforePaint event, which is sent before repainting the window if the event has been requested by a call to the Window.mozRequestAnimationFrame() method.
Window.onpaint
An event handler property for paint events on the window.
Window.onpopstate
An event handler property for popstate events, which are fired when navigating to a session history entry representing a state object.
Window.onreset
An event handler property for reset events on the window.
Window.onresize
An event handler property for window resizing.
Window.onscroll
An event handler property for window scrolling.
Window.onselect
An event handler property for window selection.
Window.onsubmit
An event handler property for submits on window forms.
Window.onunload
An event handler property for unload events on the window.
Window.onuserproximity
An event handler property for user proximity events
Window.onpageshow
An event handler property for pageshow events on the window.
Window.onpagehide
An event handler property for pagehide events on the window.

Constructors

See also the DOM Interfaces.

Window.DOMParser
FIXME: NeedsContents
Window.GeckoActiveXObject
FIXME: NeedsContents
Image
Used for creating an HTMLImageElement.
Option
Used for creating an HTMLOptionElement
Window.QueryInterface
FIXME: NeedsContents
Window.XMLSerializer
FIXME: NeedsContents
Worker
Used for creating a Web worker
Window.XPCNativeWrapper
FIXME: NeedsContents
Window.XPCSafeJSObjectWrapper
FIXME: NeedsContents

Interfaces

See DOM Reference

See also

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