Window

The Window interface 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.

A global variable, window, representing the window in which the script is running, is exposed to JavaScript code.

The Window interface is home to a variety of functions, namespaces, objects, and constructors which are not necessarily directly associated with the concept of a user interface window. However, the Window interface is a suitable place to include these items that need to be globally available. Many of these are documented in the JavaScript Reference and the DOM Reference.

In a tabbed browser, each tab is represented by its own Window object; the global window seen by JavaScript code running within a given tab always represents the tab in which the code is running. That said, even in a tabbed browser, some properties and methods still apply to the overall window that contains the tab, such as resizeTo() and innerHeight. Generally, anything that can't reasonably pertain to a tab pertains to the window instead.

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Constructors

See also the DOM Interfaces.

DOMParser

DOMParser can parse XML or HTML source stored in a string into a DOM Document. DOMParser is specified in DOM Parsing and Serialization.

Image

Used for creating an HTMLImageElement.

Option

Used for creating an HTMLOptionElement.

StaticRange Read only

Returns a StaticRange() constructor which creates a StaticRange object.

Worker

Used for creating a Web worker.

XMLSerializer

Converts a DOM tree into XML or HTML source.

Properties

This interface inherits properties from the EventTarget interface and implements properties from the WindowOrWorkerGlobalScope and WindowEventHandlers mixins.

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

Window.closed Read only

This property indicates whether the current window is closed or not.

Window.console Read only

Returns a reference to the console object which provides access to the browser's debugging console.

Window.controllers Read only

Returns the XUL controller objects for the current chrome window.

Window.customElements Read only

Returns a reference to the CustomElementRegistry object, which can be used to register new custom elements and get information about previously registered custom elements.

Window.crypto Read only

Returns the browser crypto object.

Window.devicePixelRatio Read only

Returns the ratio between physical pixels and device independent pixels in the current display.

Window.document Read only

Returns a reference to the document that the window contains.

Window.DOMMatrix Read only

Returns a reference to a DOMMatrix object, which represents 4x4 matrices, suitable for 2D and 3D operations.

Window.DOMMatrixReadOnly Read only

Returns a reference to a DOMMatrixReadOnly object, which represents 4x4 matrices, suitable for 2D and 3D operations.

Window.DOMPoint Read only

Returns a reference to a DOMPoint object, which represents a 2D or 3D point in a coordinate system.

Window.DOMPointReadOnly Read only

Returns a reference to a DOMPointReadOnly object, which represents a 2D or 3D point in a coordinate system.

Window.DOMQuad Read only

Returns a reference to a DOMQuad object, which provides represents a quadrilaterial object, that is one having four corners and four sides.

Window.DOMRect Read only

Returns a reference to a DOMRect object, which represents a rectangle.

Window.DOMRectReadOnly Read only

Returns a reference to a DOMRectReadOnly object, which represents a rectangle.

Window.event Read only

Returns the current event, which is the event currently being handled by the JavaScript code's context, or undefined if no event is currently being handled. The Event object passed directly to event handlers should be used instead whenever possible.

Window.frameElement Read only

Returns the element in which the window is embedded, or null if the window is not embedded.

Window.frames Read only

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.history Read only

Returns a reference to the history object.

Window.innerHeight Read only

Gets the height of the content area of the browser window including, if rendered, the horizontal scrollbar.

Window.innerWidth Read only

Gets the width of the content area of the browser window including, if rendered, the vertical scrollbar.

Window.isSecureContext Read only

Indicates whether a context is capable of using features that require secure contexts.

Window.length Read only

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 Read only

Returns the locationbar object, whose visibility can be toggled in the window.

Window.localStorage Read only

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 Read only

Returns the menubar object, whose visibility can be toggled in the window.

Window.messageManager

Returns the message manager object for this window.

Window.mozInnerScreenX Read only

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 Read only

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.name

Gets/sets the name of the window.

Window.navigator Read only

Returns a reference to the navigator object.

Window.opener

Returns a reference to the window that opened this current window.

Window.outerHeight Read only

Gets the height of the outside of the browser window.

Window.outerWidth Read only

Gets the width of the outside of the browser window.

Window.pageXOffset Read only

An alias for window.scrollX.

Window.pageYOffset Read only

An alias for window.scrollY

Window.parent Read only

Returns a reference to the parent of the current window or subframe.

Window.performance Read only

Returns a Performance object, which includes the timing and navigation attributes, each of which is an object providing performance-related data. See also Using Navigation Timing for additional information and examples.

Window.personalbar Read only

Returns the personalbar object, whose visibility can be toggled in the window.

Window.screen Read only

Returns a reference to the screen object associated with the window.

Window.screenX and Window.screenLeft Read only

Both properties return the horizontal distance from the left border of the user's browser viewport to the left side of the screen.

Window.screenY and Window.screenTop Read only

Both properties return the vertical distance from the top border of the user's browser viewport to the top side of the screen.

Window.scrollbars Read only

Returns the scrollbars object, whose visibility can be toggled in the window.

Window.scrollMaxX Read only

The maximum offset that the window can be scrolled to horizontally, that is the document width minus the viewport width.

Window.scrollMaxY Read only

The maximum offset that the window can be scrolled to vertically (i.e., the document height minus the viewport height).

Window.scrollX Read only

Returns the number of pixels that the document has already been scrolled horizontally.

Window.scrollY Read only

Returns the number of pixels that the document has already been scrolled vertically.

Window.self Read only

Returns an object reference to the window object itself.

Window.sessionStorage

Returns a reference to the session storage object used to store data that may only be accessed by the origin that created it.

Window.sidebar Read only

Returns a reference to the window object of the sidebar.

Window.speechSynthesis Read only

Returns a SpeechSynthesis object, which is the entry point into using Web Speech API speech synthesis functionality.

Window.status

Gets/sets the text in the statusbar at the bottom of the browser.

Window.statusbar Read only

Returns the statusbar object, whose visibility can be toggled in the window.

Window.toolbar Read only

Returns the toolbar object, whose visibility can be toggled in the window.

Window.top Read only

Returns a reference to the topmost window in the window hierarchy. This property is read only.

Window.visualViewport Read only

Returns a VisualViewport object which represents the visual viewport for a given window.

Window.window Read only

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.

Properties implemented from elsewhere

WindowOrWorkerGlobalScope.caches Read only

Returns the CacheStorage object associated with the current context. This object enables functionality such as storing assets for offline use, and generating custom responses to requests.

WindowOrWorkerGlobalScope.indexedDB Read only

Provides a mechanism for applications to asynchronously access capabilities of indexed databases; returns an IDBFactory object.

WindowOrWorkerGlobalScope.isSecureContext Read only

Returns a boolean indicating whether the current context is secure (true) or not (false).

WindowOrWorkerGlobalScope.origin Read only

Returns the global object's origin, serialized as a string. (This does not yet appear to be implemented in any browser.)

Deprecated properties

Window.content and Window._content Read only

Returns a reference to the content element in the current window. Since Firefox 57 (initially Nightly-only), both versions are only available from chrome (privileged) code, and not available to the web anymore.

Window.defaultStatus

Gets/sets the status bar text for the given window.

Window.dialogArguments Read only

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.globalStorage

Multiple storage objects that were used for storing data across multiple pages.

Window.mozAnimationStartTime

The time in milliseconds since epoch at which the current animation cycle began. Use Animation.startTime instead.

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.orientation Read only

Returns the orientation in degrees (in 90 degree increments) of the viewport relative to the device's natural orientation.

Window.pkcs11

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.

Methods

This interface inherits methods from the EventTarget interface and implements methods from WindowOrWorkerGlobalScope and EventTarget.

Window.alert()

Displays an alert dialog.

Window.blur()

Sets focus away from the window.

Window.cancelAnimationFrame()

Enables you to cancel a callback previously scheduled with Window.requestAnimationFrame.

Window.cancelIdleCallback()

Enables you to cancel a callback previously scheduled with Window.requestIdleCallback.

Window.clearImmediate()

Cancels the repeated execution set using setImmediate.

Window.close()

Closes the current window.

Window.confirm()

Displays a dialog with a message that the user needs to respond to.

Window.dump()

Writes a message to the console.

Window.find()

Searches for a given string in a window.

Window.focus()

Sets focus on the current window.

Window.getComputedStyle()

Gets computed style for the specified element. Computed style indicates the computed values of all CSS properties of the element.

Window.getDefaultComputedStyle()

Gets default computed style for the specified element, ignoring author stylesheets.

Window.getSelection()

Returns the selection object representing the selected item(s).

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.open()

Opens a new 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.

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.requestAnimationFrame()

Tells the browser that an animation is in progress, requesting that the browser schedule a repaint of the window for the next animation frame.

Window.requestIdleCallback()

Enables the scheduling of tasks during a browser's idle periods.

Window.resizeBy()

Resizes the current window by a certain amount.

Window.resizeTo()

Dynamically resizes window.

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.setImmediate()

Executes a function after the browser has finished other heavy tasks

Window.setResizable()

Toggles a user's ability to resize a window.

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).

Methods implemented from elsewhere

EventTarget.addEventListener()

Register an event handler to a specific event type on the window.

EventTarget.dispatchEvent()

Used to trigger an event.

WindowOrWorkerGlobalScope.atob()

Decodes a string of data which has been encoded using base-64 encoding.

WindowOrWorkerGlobalScope.btoa()

Creates a base-64 encoded ASCII string from a string of binary data.

WindowOrWorkerGlobalScope.clearInterval()

Cancels the repeated execution set using WindowOrWorkerGlobalScope.setInterval().

WindowOrWorkerGlobalScope.clearTimeout()

Cancels the delayed execution set using WindowOrWorkerGlobalScope.setTimeout().

WindowOrWorkerGlobalScope.createImageBitmap()

Accepts a variety of different image sources, and returns a Promise which resolves to an ImageBitmap. Optionally the source is cropped to the rectangle of pixels originating at (sx, sy) with width sw, and height sh.

WindowOrWorkerGlobalScope.fetch()

Starts the process of fetching a resource from the network.

EventTarget.removeEventListener

Removes an event listener from the window.

WindowOrWorkerGlobalScope.setInterval()

Schedules a function to execute every time a given number of milliseconds elapses.

WindowOrWorkerGlobalScope.setTimeout()

Schedules a function to execute in a given amount of time.

Deprecated methods

Window.back()

Moves back one in the window history. This method is deprecated; you should instead use window.history.back().

Window.captureEvents()

Registers the window to capture all events of the specified type.

Window.forward()

Moves the window one document forward in the history. This method is deprecated; you should instead use window.history.forward().

Window.getAttention()

Flashes the application icon.

Window.home()

Returns the browser to the home page.

Window.openDialog()

Opens a new dialog window.

Window.releaseEvents()

Releases the window from trapping events of a specific type.

Window.showModalDialog()

Displays a modal dialog.

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.

This interface inherits event handlers from the EventTarget interface and implements event handlers from WindowEventHandlers.

Window.onappinstalled

Called when the page is installed as a webapp. See appinstalled event.

Window.onbeforeinstallprompt

An event handler property dispatched before a user is prompted to save a web site to a home screen on mobile.

Window.ondevicelight

An event handler property for any ambient light levels changes

Window.ondevicemotion

Called if accelerometer detects a change (For mobile devices)

Window.ondeviceorientation

Called when the orientation is changed (For mobile devices)

Window.ondeviceorientationabsolute

An event handler property for any device orientation changes.

Window.ondeviceproximity

An event handler property for device proximity event

Window.ongamepadconnected

Represents an event handler that will run when a gamepad is connected (when the gamepadconnected event fires).

Window.ongamepaddisconnected

Represents an event handler that will run when a gamepad is disconnected (when the gamepaddisconnected event fires).

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.onrejectionhandled

An event handler for handled Promise rejection events.

Window.onuserproximity

An event handler property for user proximity events.

Event handlers implemented from elsewhere

GlobalEventHandlers.onabort

Called when the loading of a resource has been aborted, such as by a user canceling the load while it is still in progress

WindowEventHandlers.onafterprint

Called when the print dialog box is closed. See afterprint event.

WindowEventHandlers.onbeforeprint

Called when the print dialog box is opened. See beforeprint event.

WindowEventHandlers.onbeforeunload

An event handler property for before-unload events on the window.

GlobalEventHandlers.onblur

Called after the window loses focus, such as due to a popup.

GlobalEventHandlers.onchange

An event handler property for change events on the window.

GlobalEventHandlers.onclick

Called after the ANY mouse button is pressed & released

GlobalEventHandlers.ondblclick

Called when a double click is made with ANY mouse button.

GlobalEventHandlers.onclose

Called after the window is closed

GlobalEventHandlers.oncontextmenu

Called when the RIGHT mouse button is pressed

GlobalEventHandlers.onerror

Called when a resource fails to load OR when an error occurs at runtime. See error event.

GlobalEventHandlers.onfocus

Called after the window receives or regains focus. See focus events.

WindowEventHandlers.onhashchange

An event handler property for hashchange events on the window; called when the part of the URL after the hash mark ("#") changes.

GlobalEventHandlers.oninput

Called when the value of an <input> element changes

GlobalEventHandlers.onkeydown

Called when you begin pressing ANY key. See keydown event.

GlobalEventHandlers.onkeypress

Called when a key (except Shift, Fn, and CapsLock) is in pressed position. See keypress event.

GlobalEventHandlers.onkeyup

Called when you finish releasing ANY key. See keyup event.

WindowEventHandlers.onlanguagechange

An event handler property for languagechange events on the window.

GlobalEventHandlers.onload

Called after all resources and the DOM are fully loaded. WILL NOT get called when the page is loaded from cache, such as with back button.

WindowEventHandlers.onmessage

Is an EventHandler representing the code to be called when the message event is raised.

GlobalEventHandlers.onmousedown

Called when ANY mouse button is pressed.

GlobalEventHandlers.onmousemove

Called continously when the mouse is moved inside the window.

GlobalEventHandlers.onmouseout

Called when the pointer leaves the window.

GlobalEventHandlers.onmouseover

Called when the pointer enters the window

GlobalEventHandlers.onmouseup

Called when ANY mouse button is released

WindowEventHandlers.onoffline

Called when network connection is lost. See offline event.

WindowEventHandlers.ononline

Called when network connection is established. See online event.

WindowEventHandlers.onpagehide

Called when the user navigates away from the page, before the onunload event. See pagehide event.

WindowEventHandlers.onpageshow

Called after all resources and the DOM are fully loaded. See pageshow event.

WindowEventHandlers.onpopstate

Called when a back button is pressed.

GlobalEventHandlers.onreset

Called when a form is reset

GlobalEventHandlers.onresize

Called continuously as you are resizing the window.

GlobalEventHandlers.onscroll

Called when the scroll bar is moved via ANY means. If the resource fully fits in the window, then this event cannot be invoked

GlobalEventHandlers.onwheel

Called when the mouse wheel is rotated around any axis

GlobalEventHandlers.onselect

Called after text in an input field is selected

GlobalEventHandlers.onselectionchange

Is an EventHandler representing the code to be called when the selectionchange event is raised.

WindowEventHandlers.onstorage

Called when there is a change in session storage or local storage. See storage event

GlobalEventHandlers.onsubmit

Called when a form is submitted

WindowEventHandlers.onunhandledrejection

An event handler for unhandled Promise rejection events.

WindowEventHandlers.onunload

Called when the user navigates away from the page.

Events

Listen to these events using addEventListener() or by assigning an event listener to the oneventname property of this interface.

error

Fired when a resource failed to load, or can't be used. For example, if a script has an execution error or an image can't be found or is invalid.
Also available via the onerror property.

languagechange

Fired at the global scope object when the user's preferred language changes.
Also available via the onlanguagechange property.

orientationchange

Fired when the orientation of the device has changed.
Also available via the onorientationchange property.

devicemotion

Fired at a regular interval, indicating the amount of physical force of acceleration the device is receiving and the rate of rotation, if available.

deviceorientation

Fired when fresh data is available from the magnetometer orientation sensor about the current orientation of the device as compared to the Earth coordinate frame.

resize

Fired when the window has been resized.
Also available via the onresize property.

storage

Fired when a storage area (localStorage or sessionStorage) has been modified in the context of another document.
Also available via the onstorage property.

Animation events

animationcancel

Fired when an animation unexpectedly aborts.
Also available via the onanimationcancel property.

animationend

Fired when an animation has completed normally.
Also available via the onanimationend property.

animationiteration

Fired when an animation iteration has completed.
Also available via the onanimationiteration property.

animationstart

Fired when an animation starts.
Also available via the onanimationstart property.

Clipboard events

clipboardchange

Fired when the system clipboard content changes.

copy

Fired when the user initiates a copy action through the browser's user interface.
Also available via the oncopy property.

cut

Fired when the user initiates a cut action through the browser's user interface.
Also available via the oncut property.

paste

Fired when the user initiates a paste action through the browser's user interface.
Also available via the onpaste property.

Connection events

offline

Fired when the browser has lost access to the network and the value of navigator.onLine has switched to false.
Also available via the onoffline property.

online

Fired when the browser has gained access to the network and the value of navigator.onLine has switched to true.
Also available via the ononline property.

Focus events

blur

Fired when an element has lost focus.
Also available via the onblur property.

focus

Fired when an element has gained focus.
Also available via the onfocus property

Gamepad events

gamepadconnected

Fired when the browser detects that a gamepad has been connected or the first time a button/axis of the gamepad is used.
Also available via the ongamepadconnected property.

gamepaddisconnected

Fired when the browser detects that a gamepad has been disconnected.
Also available via the ongamepaddisconnected property

History events

hashchange

Fired when the fragment identifier of the URL has changed (the part of the URL beginning with and following the # symbol).
Also available via the onhashchange property.

pagehide

Sent when the browser hides the current document while in the process of switching to displaying in its place a different document from the session's history. This happens, for example, when the user clicks the Back button or when they click the Forward button to move ahead in session history.
Also available through the onpagehide event handler property.

pageshow

Sent when the browser makes the document visible due to navigation tasks, including not only when the page is first loaded, but also situations such as the user navigating back to the page after having navigated to another within the same tab.
Also available using the onpageshow event handler property.

popstate

Fired when the active history entry changes.
Also available using the onpopstate event handler property.

Load & unload events

beforeunload

Fired when the window, the document and its resources are about to be unloaded.
Also available via the onbeforeunload property.

DOMContentLoaded

Fired when the document has been completely loaded and parsed, without waiting for stylesheets, images, and subframes to finish loading.

load

Fired when the whole page has loaded, including all dependent resources such as stylesheets images.
Also available via the onload property.

unload

Fired when the document or a child resource is being unloaded.
Also available via the onunload property.

Manifest events

appinstalled

Fired when the browser has successfully installed a page as an application.
Also available via the onappinstalled property.

beforeinstallprompt

Fired when a user is about to be prompted to install a web application.
Also available via the onbeforeinstallprompt property.

Messaging events

message

Fired when the window receives a message, for example from a call to Window.postMessage() from another browsing context.
Also available via the onmessage property.

messageerror

Fired when a Window object receives a message that can't be deserialized.
Also available via the onmessageerror property.

Print events

afterprint

Fired after the associated document has started printing or the print preview has been closed.
Also available via the onafterprint property.

beforeprint

Fired when the associated document is about to be printed or previewed for printing.
Also available via the onbeforeprint property.

Promise rejection events

rejectionhandled

Sent every time a JavaScript Promise is rejected, regardless of whether or not there is a handler in place to catch the rejection.
Also available through the onrejectionhandled event handler property.

unhandledrejection

Sent when a JavaScript Promise is rejected but there is no handler in place to catch the rejection.
Also available using the onunhandledrejection event handler property.

Transition events

transitioncancel

Fired when a CSS transition is canceled.
Also available via the ontransitioncancel property.

transitionend

Fired when a CSS transition has completed.
Also available via the ontransitionend property.

transitionrun

Fired when a CSS transition is first created.
Also available via the ontransitionrun property.

transitionstart

Fired when a CSS transition has actually started.
Also available via the ontransitionstart property.

Interfaces

See DOM Reference.

Browser compatibility