TheWindow interface represents a window containing aDOM document; thedocument property points to theDOM document loaded in that window.

A window for a given document can be obtained using thedocument.defaultView property.

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

TheWindow 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, theWindow interface is a suitable place to include these items that need to be globally available. Many of these are documented in theJavaScript Reference and theDOM Reference.

In a tabbed browser, each tab is represented by its ownWindow object; the globalwindow 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 asresizeTo() andinnerHeight. Generally, anything that can't reasonably pertain to a tab pertains to the window instead.

Instance properties

This interface inherits properties from theEventTarget interface.

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

Window.cachesRead onlySecure context

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

Window.clientInformationRead only

An alias forWindow.navigator.

Window.closedRead only

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

Window.cookieStoreRead onlySecure context

Returns a reference to theCookieStore object for the current document context.

Window.credentiallessRead onlyExperimental

Returns a boolean that indicates whether the current document was loaded inside a credentialless<iframe>. SeeIFrame credentialless for more details.

Window.crossOriginIsolatedRead only

Returns a boolean value that indicates whether the website is in a cross-origin isolation state.

Window.cryptoRead only

Returns theCrypto object associated to the global object.

Window.customElementsRead only

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

Window.devicePixelRatioRead only

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

Window.documentRead only

Returns a reference to the document that the window contains.

Window.documentPictureInPictureRead onlyExperimentalSecure context

Returns a reference to thedocument Picture-in-Picture window for the current document context.

Window.fenceRead onlyExperimental

Returns aFence object instance for the current document context. Available only to documents embedded inside a<fencedframe>.

Window.frameElementRead only

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

Window.framesRead only

Returns an array of the subframes in the current window.

Window.fullScreenNon-standard

This property indicates whether the window is displayed in full screen or not.

Window.historyRead only

Returns a reference to the history object.

Window.indexedDBRead only

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

Window.innerHeightRead only

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

Window.innerWidthRead only

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

Window.isSecureContextRead only

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

Window.launchQueueRead onlyExperimental

When aprogressive web app (PWA) is launched with alaunch_handlerclient_mode value offocus-existing,navigate-new, ornavigate-existing, thelaunchQueue provides access to theLaunchQueue class, which allows custom launch navigation handling to be implemented for the PWA.

Window.lengthRead only

Returns the number of frames in the window. See alsowindow.frames.

Window.localStorageRead 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.location

Gets/sets the location, or current URL, of the window object.

Window.locationbarRead only

Returns the locationbar object.

Window.menubarRead only

Returns the menubar object.

Window.mozInnerScreenXRead onlyNon-standard

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. SeemozScreenPixelsPerCSSPixel innsIDOMWindowUtils for a conversion factor to adapt to screen pixels if needed.

Window.mozInnerScreenYRead onlyNon-standard

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. SeemozScreenPixelsPerCSSPixel for a conversion factor to adapt to screen pixels if needed.

Window.name

Gets/sets the name of the window.

Window.navigationRead onlyExperimental

Returns the currentwindow's associatedNavigation object. The entry point for theNavigation API.

Window.navigatorRead only

Returns a reference to the navigator object.

Window.opener

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

Window.originRead only

Returns the global object's origin, serialized as a string.

Window.originAgentClusterRead only

Returnstrue if this window belongs to an origin-keyed agent cluster.

Window.outerHeightRead only

Gets the height of the outside of the browser window.

Window.outerWidthRead only

Gets the width of the outside of the browser window.

Window.pageXOffsetRead only

An alias forwindow.scrollX.

Window.pageYOffsetRead only

An alias forwindow.scrollY.

Window.parentRead only

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

Window.performanceRead only

Returns aPerformance object, which includes thetiming andnavigation attributes, each of which is an object providingperformance-related data. See alsoUsing Navigation Timing for additional information and examples.

Window.personalbarRead only

Returns the personalbar object.

Window.schedulerRead only

Returns theScheduler object associated with the current context. This is the entry point for using thePrioritized Task Scheduling API.

Window.screenRead only

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

Window.screenX andWindow.screenLeftRead 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 andWindow.screenTopRead 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.scrollbarsRead only

Returns the scrollbars object.

Window.scrollMaxXNon-standardRead only

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

Window.scrollMaxYNon-standardRead only

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

Window.scrollXRead only

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

Window.scrollYRead only

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

Window.selfRead 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.sharedStorageRead onlyExperimentalSecure context

Returns theWindowSharedStorage object for the current origin. This is the main entry point for writing data to shared storage using theShared Storage API.

Window.speechSynthesisRead only

Returns aSpeechSynthesis object, which is the entry point into usingWeb Speech API speech synthesis functionality.

Window.statusbarRead only

Returns the statusbar object.

Window.toolbarRead only

Returns the toolbar object.

Window.topRead only

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

Window.trustedTypesRead only

Returns theTrustedTypePolicyFactory object associated with the global object, providing the entry point for using theTrusted Types API.

Window.viewportExperimentalRead only

Returns aViewport object instance, which provides information about the current state of the device's viewport.

Window.visualViewportRead only

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

Window.windowRead only

Returns a reference to the current window.

window[0],window[1], etc.

Returns a reference to thewindow object in the frames. SeeWindow.frames for more details.

Named properties

Some elements in the document are also exposed as window properties:

• For each<embed>,<form>,<iframe>,<img>, and<object> element, itsname (if non-empty) is exposed.For example, if the document contains<form name="my_form">, thenwindow["my_form"] (and its equivalentwindow.my_form) returns a reference to that element.
• For each HTML element, itsid (if non-empty) is exposed.

If a property corresponds to a single element, that element is directly returned. If the property corresponds to multiple elements, then anHTMLCollection is returned containing all of them. If any of the elements is a navigable<iframe> or<object>, then thecontentWindow of first such iframe is returned instead.

Deprecated properties

Window.eventDeprecatedRead only

Returns thecurrent event, which is the event currently being handled by the JavaScript code's context, orundefined if no event is currently being handled. TheEvent object passed directly to event handlers should be used instead whenever possible.

Window.externalDeprecatedRead only

Returns an object with functions for adding external search providers to the browser.

Window.orientationDeprecatedRead only

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

Window.statusDeprecated

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

Instance methods

This interface inherits methods from theEventTarget interface.

Window.atob()

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

Window.alert()

Displays an alert dialog.

Window.blur()Deprecated

Sets focus away from the window.

Window.btoa()

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

Window.cancelAnimationFrame()

Enables you to cancel a callback previously scheduled withWindow.requestAnimationFrame.

Window.cancelIdleCallback()

Enables you to cancel a callback previously scheduled withWindow.requestIdleCallback.

Window.clearInterval()

Cancels the repeated execution set usingWindow.setInterval().

Window.clearTimeout()

Cancels the delayed execution set usingWindow.setTimeout().

Window.close()

Closes the current window.

Window.confirm()

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

Window.createImageBitmap()

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

Window.dump()Non-standard

Writes a message to the console.

Window.fetch()

Starts the process of fetching a resource from the network.

Window.fetchLater()Experimental

Creates a deferred fetch, which is sent once the page is navigated away from (it is destroyed or enters thebfcache), or after a providedactivateAfter timeout — whichever comes first.

Window.find()Non-standard

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()Non-standard

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

Window.getScreenDetails()ExperimentalSecure context

Returns aPromise that fulfills with aScreenDetails object instance representing the details of all the screens available to the user's device.

Window.getSelection()

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

Window.matchMedia()

Returns aMediaQueryList object representing the specified media query string.

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.queryLocalFonts()ExperimentalSecure context

Returns aPromise that fulfills with an array ofFontData objects representing the font faces available locally.

Window.queueMicrotask()

Queues a microtask to be executed at a safe time prior to control returning to the browser's event loop.

Window.reportError()

Reports an error in a script, emulating an unhandled exception.

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()Non-standard

Scrolls the document by the given number of lines.

Window.scrollByPages()Non-standard

Scrolls the current document by the specified number of pages.

Window.scrollTo()

Scrolls to a particular set of coordinates in the document.

Window.setInterval()

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

Window.setTimeout()

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

Window.showDirectoryPicker()ExperimentalSecure context

Displays a directory picker which allows the user to select a directory.

Window.showOpenFilePicker()ExperimentalSecure context

Shows a file picker that allows a user to select a file or multiple files.

Window.showSaveFilePicker()ExperimentalSecure context

Shows a file picker that allows a user to save a file.

Window.sizeToContent()Non-standard

Sizes the window according to its content.

Window.stop()

This method stops window loading.

Window.structuredClone()

Creates adeep clone of a given value using thestructured clone algorithm.

Deprecated methods

Window.captureEvents()Deprecated

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

Window.clearImmediate()Non-standardDeprecated

Cancels the repeated execution set usingsetImmediate().

Window.releaseEvents()Deprecated

Releases the window from trapping events of a specific type.

Window.requestFileSystem()Non-standardDeprecated

Lets a website or app gain access to a sandboxed file system for its own use.

Window.setImmediate()Non-standardDeprecated

Executes a function after the browser has finished other heavy tasks.

Window.setResizable()Non-standardDeprecated

Does nothing (no-op). Kept for backward compatibility with Netscape 4.x.

Window.webkitConvertPointFromNodeToPage()Non-standardDeprecated

Transforms aWebKitPoint from the node's coordinate system to the page's coordinate system.

Window.webkitConvertPointFromPageToNode()Non-standardDeprecated

Transforms aWebKitPoint from the page's coordinate system to the node's coordinate system.

Events

Listen to these events usingaddEventListener() or by assigning an event listener to theoneventname property of this interface. In addition to the events listed below, many events can bubble from theDocument contained in the window object.

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.

languagechange

Fired at the global scope object when the user's preferred language changes.

resize

Fired when the window has been resized.

storage

Fired when a storage area (localStorage orsessionStorage) has been modified in the context of another document.

Connection events

offline

Fired when the browser has lost access to the network and the value ofnavigator.onLine has switched tofalse.

online

Fired when the browser has gained access to the network and the value ofnavigator.onLine has switched totrue.

Device orientation events

devicemotionSecure context

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

deviceorientationSecure context

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.

deviceorientationabsoluteSecure context

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

Focus events

blur

Fired when an element has lost focus.

focus

Fired when an element has gained focus.

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.

gamepaddisconnected

Fired when the browser detects that a gamepad has been disconnected.

History events

hashchange

Fired when the fragment identifier of the URL has changed (the part of the URL beginning with and following the# symbol).

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.

pagereveal

Fired when a document is first rendered, either when loading a fresh document from the network or activating a document (either fromback/forward cache (bfcache) orprerender).

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.

pageswap

Fired when a document is about to be unloaded due to a navigation.

popstate

Fired when the active history entry changes.

Load & unload events

beforeunload

Fired when the window, the document and its resources are about to be unloaded.

load

Fired when the whole page has loaded, including all dependent resources such as stylesheets images.

unload

Fired when the document or a child resource is being unloaded.

Manifest events

appinstalled

Fired when the browser has successfully installed a page as an application.

beforeinstallprompt

Fired when a user is about to be prompted to install a web application.

Messaging events

message

Fired when the window receives a message, for example from a call toWindow.postMessage() from another browsing context.

messageerror

Fired when aWindow object receives a message that can't be deserialized.

Print events

afterprint

Fired after the associated document has started printing or the print preview has been closed.

beforeprint

Fired when the associated document is about to be printed or previewed for printing.

Promise rejection events

rejectionhandled

Sent every time a JavaScriptPromise is rejected, regardless of whether or not there is a handler in place to catch the rejection.

unhandledrejection

Sent when a JavaScriptPromise is rejected but there is no handler in place to catch the rejection.

Scroll events

scrollsnapchangeExperimental

Fired on the scroll container at the end of a scrolling operation when a new scroll snap target has been selected.

scrollsnapchangingExperimental

Fired on the scroll container when the browser determines a new scroll snap target is pending, i.e., it will be selected when the current scroll gesture ends.

Deprecated events

orientationchangeDeprecated

Fired when the orientation of the device has changed.

vrdisplayactivateDeprecatedNon-standard

Fired when a display is able to be presented to.

vrdisplayconnectDeprecatedNon-standard

Fired when a compatible VR device has been connected to the computer.

vrdisplaydisconnectDeprecatedNon-standard

Fired when a compatible VR device has been disconnected from the computer.

vrdisplaydeactivateDeprecatedNon-standard

Fired when a display can no longer be presented to.

vrdisplaypresentchangeDeprecatedNon-standard

Fired when the presenting state of a VR device changes — i.e., goes from presenting to not presenting, or vice versa.

Bubbled events

Not all events that bubble can reach theWindow object. Only the following do and can be listened for on theWindow object:

• abort
• auxclick
• beforeinput
• beforematch
• beforetoggle
• cancel
• canplay
• canplaythrough
• change
• click
• close
• contextlost
• contextmenu
• contextrestored
• copy
• cuechange
• cut
• dblclick
• drag
• dragend
• dragenter
• dragleave
• dragover
• dragstart
• drop
• durationchange
• emptied
• ended
• formdata
• input
• invalid
• keydown
• keypress
• keyup
• loadeddata
• loadedmetadata
• loadstart
• mousedown
• mouseenter
• mouseleave
• mousemove
• mouseout
• mouseover
• mouseup
• paste
• pause
• play
• playing
• progress
• ratechange
• reset
• scrollend
• securitypolicyviolation
• seeked
• seeking
• select
• slotchange
• stalled
• submit
• suspend
• timeupdate
• toggle
• volumechange
• waiting
• wheel

Interfaces

SeeDOM Reference.

Listening for events on Window

HTML elements have three ways to listen for events:

• Add an event listener to the element using theEventTarget.addEventListener method.
• Assign an event handler to the element'soneventname property in JavaScript.
• Add anon-prefixed attribute to the element in the HTML.

To listen for events onWindow objects, in general, you can only use the first two methods, becauseWindow has no corresponding HTML element. However, there's a specific group of events whose listeners can be added to the<body> (or the deprecated<frameset>) element that's owned by theWindow's document, using the second or third methods. These events are:

• afterprint
• beforeprint
• beforeunload
• blur
• error
• focus
• hashchange
• languagechange
• load
• message
• messageerror
• offline
• online
• pagehide
• pagereveal
• pageshow
• pageswap
• popstate
• rejectionhandled
• resize
• scroll
• storage
• unhandledrejection
• unload

This means the following are strictly equivalent:

window.onresize = (e) => console.log(e.currentTarget);document.body.onresize = (e) => console.log(e.currentTarget);

<body onresize="console.log(event.currentTarget)"></body>

In all three cases, you see theWindow object logged ascurrentTarget.

Specifications

Browser compatibility