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.

Constructors

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.clientInformation Read only: An alias for Window.navigator.
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.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.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.
isSecureContext Read only: Returns a boolean indicating whether the current context is secure (true) or not (false).
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

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.
indexedDB Read only: Provides a mechanism for applications to asynchronously access capabilities of indexed databases; returns an IDBFactory object.
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.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.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.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.showOpenFilePicker(): Shows a file picker that allows a user to select a file or multiple files.
Window.showSaveFilePicker(): Shows a file picker that allows a user to save a file.
Window.showDirectoryPicker(): Displays a directory picker which allows the user to select a directory.
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.
atob(): Decodes a string of data which has been encoded using base-64 encoding.
btoa(): Creates a base-64 encoded ASCII string from a string of binary data.
clearInterval(): Cancels the repeated execution set using setInterval().
clearTimeout(): Cancels the delayed execution set using setTimeout().
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.
fetch(): Starts the process of fetching a resource from the network.
EventTarget.removeEventListener(): Removes an event listener from the window.
setInterval(): Schedules a function to execute every time a given number of milliseconds elapses.
setTimeout(): Schedules a function to execute in a given amount of time.
reportError(): Reports an error in a script, emulating an unhandled exception.

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.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.

WindowEventHandlers.onrejectionhandled: An event handler for handled Promise rejection events.
Window.onuserproximity: An event handler property for user proximity events (see UserProximityEvent).

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.
GlobalEventHandlers.onmousedown: Called when ANY mouse button is pressed.
GlobalEventHandlers.onmousemove: Called continuously 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 event handler 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.
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.
vrdisplayconnect: Fired when a compatible VR device has been connected to the computer.
vrdisplaydisconnect: Fired when a compatible VR device has been disconnected from the computer.
vrdisplayactivate: Fired when a display is able to be presented to.
vrdisplaydeactivate: Fired when a display can no longer be presented to.
vrdisplayblur: Fired when presentation to a display has been paused for some reason by the browser, OS, or VR hardware.
vrdisplayfocus: Fired when presentation to a display has resumed after being blurred.
vrdisplaypresentchange: Fired when the presenting state of a VR device changes — i.e. goes from presenting to not presenting, or vice versa.

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

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.
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). 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.
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 to Window.postMessage() from another browsing context.
messageerror: Fired when a Window 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. 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.

WebVR events

vrdisplayactivate: Fired when a VR display becomes available to be presented to, for example if an HMD has been moved to bring it out of standby, or woken up by being put on. Also available via the onvrdisplayactivate property.
vrdisplayblur: Fired when presentation to a VR display has been paused for some reason by the browser, OS, or VR hardware. Also available via the onvrdisplayblur property.
vrdisplayconnect: Fired when a compatible VR display is connected to the computer. Also available via the onvrdisplayconnect property.
vrdisplaydeactivate: Fired when a VR display can no longer be presented to, for example if an HMD has gone into standby or sleep mode due to a period of inactivity. Also available via the onvrdisplaydeactivate property.
vrdisplaydisconnect: Fired when a compatible VR display is disconnected from the computer. Also available via the onvrdisplaydisconnect property.
vrdisplayfocus: Fired when presentation to a VR display has resumed after being blurred. Also available via the onvrdisplayfocus property.
vrdisplaypresentchange: Fired when the presenting state of a VR display changes — i.e. goes from presenting to not presenting, or vice versa. Also available via the onvrdisplaypresentchange property.
vrdisplaypointerrestricted: Fired when the VR display's pointer input is restricted to consumption via a pointerlocked element. Also available via the onvrdisplaypointerrestricted property.
vrdisplaypointerunrestricted: Fired when the VR display's pointer input is no longer restricted to consumption via a pointerlocked element. Also available via the onvrdisplaypointerunrestricted property.

Interfaces

See DOM Reference.

Specifications

Specification
HTML Standard # the-window-object

Browser compatibility

BCD tables only load in the browser