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window object

Browser support:

Represents the browser window, frame window or dialog window of a HTML document.

The window object provides various information about the window (name, navigator, location, history, etc.), provides access to the document contained by the window and supports several useful methods (alert, confirm, addEventListener, attachEvent, etc.).

The window object can also represent a window that belongs to a frame or iframe element or a modal or modeless dialog (open, showModalDialog and showModelessDialog methods).

If a window belongs to a frame or iframe element, then it is the child window of the window that contains the frame element. To get the parent window, use the parent property of the child window.
If a window is opened with the open, showModalDialog or showModelessDialog method, then the window that opened it can be retrieved with the opener property.

The members of the current window are accessible directly, without using the window object as a prefix (e.g. you can use document instead of window.document), furthermore the global variables and objects are also accessible through the window object (var x = 2; alert (window.x);).
The window object is accessible from anywhere in the JavaScript code, so do not use variables with the same names as the members of the window object (although if you declare a variable with the same name as any member of the window object, the member of the window object stays accessible through the window object).

Syntax:

Properties that reference the object:

•	window
+	object.contentWindow
	Related HTML objects: frame, iframe
•	external.menuArguments
•	document.parentWindow
•	event.source
•	event.view

Methods that return the object:

•	frames.item (nameOrIndex)

The base interface, through which you can add new functionalities to the window object, is the Window interface.

Possible members:

Properties

Methods

Events

_content

Returns a reference to the topmost ancestor window object in the window hierarchy.

clientInformation

Contains information about the browser and the operating system of the user.

clipboardData

Allows access to the data placed on the system clipboard.

closed

Returns a Boolean value that indicates whether the window is closed or not.

Components

Implements the XPConnect (Cross Platform Connect) technology that provides interaction between XPCOM (Cross Platform Component Object Model) and JavaScript.

content

Returns a reference to the topmost ancestor window object in the window hierarchy.

crypto

Represents the security object of the Firefox browser. The crypto object allows access to various browser security and cryptographic features.

defaultStatus

Sets or returns the default message in the status bar.

dialogArguments

	3

Returns a variable that was passed as an extra argument to a modal dialog window created with the window.showModalDialog or window.showModelessDialog method.

dialogHeight

Specifies or retrieves the height of the dialog window.

dialogLeft

Specifies or retrieves the left position of the dialog window.

dialogTop

Specifies or retrieves the top position of the dialog window.

dialogWidth

Specifies or retrieves the width of the dialog window.

directories

Represents a bar object in Firefox, Google Chrome and Safari.

document

Represents an entire HTML document and provides possibilities for accessing, creating and manipulating all elements in the document.

event

Represents an object that contains information about an event that has occurred.

external

Returns a reference to the external object in Internet Explorer and the sidebar object in Firefox.

frameElement

Returns a reference to the frame or iframe element that hosts the current window in the parent document.

frames

Represents a collection of all window objects that belong to frame and iframe elements in the current document.

fullScreen

	3

Specifies or retrieves whether the browser application is in full-screen mode or not.

history

Provides access to the browser history that contains the URLs of visited pages.

innerHeight

9

Returns the height of the browser's client area, including the horizontal scrollbar, if rendered.

innerWidth

9

Returns the width of the browser's client area, including the vertical scrollbar, if rendered.

length

Returns the number of frames (frame or iframe) in the current window.

location

Contains information about the URL of the currently loaded document, and provides methods to navigate to a new page.

locationbar

Represents a bar object in Firefox, Google Chrome and Safari.

menubar

Represents a bar object in Firefox, Google Chrome and Safari.

name

Sets or retrieves the name of the current window object, which is used to identify the window.

navigator

Contains information about the browser and the operating system of the user.

offscreenBuffering

Specifies or returns whether the off-screen buffer needs to be used for drawing.

opener

Sets or retrieves a reference to the window that opened the current document.

opera

Supports some Opera specific methods.

outerHeight

9

Sets or retrieves the total height of the browser window, including toolbars and scrollbars.

outerWidth

9

Sets or retrieves the total width of the browser window, including toolbars and scrollbars.

pageXOffset

9

Retrieves the number of pixels by which the contents of the document are scrolled to left.

pageYOffset

9

Retrieves the number of pixels by which the contents of the document are scrolled upward.

parent

Returns a reference to the immediate parent window object in the window hierarchy.

personalbar

Represents a bar object in Firefox, Google Chrome and Safari.

pkcs11

Retrieves a reference to the pkcs11 object. Use this object to install drivers or other software.

returnValue

	3

Specifies or retrieves the value returned from a modal dialog window.

screen

Contains information about the dimensions of the screen and the display settings.

screenLeft

Returns an integer value that indicates the horizontal position of the left side of the browser's client area, relative to the left side of the screen.

screenTop

Returns an integer value that indicates the vertical position of the top side of the browser's client area, relative to the top side of the screen.

screenX

9

Returns an integer value that indicates the horizontal position of the left side of the browser window, relative to the left side of the screen.

screenY

9

Returns an integer value that indicates the vertical position of the top side of the browser window, relative to the top side of the screen.

scrollbars

Represents a bar object in Firefox, Google Chrome and Safari.

scrollMaxX

Returns the maximum number of pixels by which the contents of the document can be scrolled horizontally.

scrollMaxY

Returns the maximum number of pixels by which the contents of the document can be scrolled vertically.

scrollX

Retrieves the number of pixels by which the contents of the document are scrolled to the left.

scrollY

Retrieves the number of pixels by which the contents of the document are scrolled upward.

self

Returns a reference to the window object itself.

sidebar

Provides methods for registering add-ons with the Firefox browser.

status

Sets the message in the status bar or retrieves the previously specified value.

statusbar

Represents a bar object in Firefox, Google Chrome and Safari.

toolbar

Represents a bar object in Firefox, Google Chrome and Safari.

top

Returns a reference to the topmost ancestor window object in the window hierarchy.

addEventListener

9

Registers an event handler function (event listener) for the specified event on the current object.

alert

Displays an alert window with the specified message and an OK button.

atob

Decodes a base-64 encoded string.

attachEvent

Registers an event handler function (event listener) for the specified event on the current object.

back

Loads the previous page form the history list into the current window.

blur

Removes the focus from the current element, and fires the onblur event.

btoa

Creates encoded data from the given string, using base-64 encoding.

captureEvents


	3

Tells the document or window object to capture the specified types of events.

clearInterval

Clears the periodically repeated action that was previously set by the setInterval method.

clearTimeout

Clears the delayed action that was previously set by the setTimeout method.

Closes the current window.

confirm

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

createPopup

Creates a popup window object.

detachEvent

Removes the specified event handler from the current element that was registered earlier with the attachEvent method.

disableExternalCapture


	3

Disables event capturing for documents that are located in different domains.

dispatchEvent

9

Dispatches the specified event to the current element.

dump

Prints the specified message to the console.

enableExternalCapture


	3

Allows event capturing for documents that are located in different domains.

execScript

Executes the specified script in the specified language.

find

Searches for a specified text in the document and highlights the matches.

focus

Sets the focus on the current element.

forward

Loads the next page form the history list into the current window.

getComputedStyle

9

Returns a CSSStyleDeclaration object that represents the computed style for the current element.

getSelection

9

Returns a selectionRange object representing the selected content in the current document.

home

Loads the browser's initial home page.

moveBy

Moves the browser window by the specified number of pixels, relative to its current coordinates.

moveTo

Moves the top-left corner of the browser window to the specified position, relative the top-left corner of the screen.

navigate

Loads the document at the specified URL into the current window.

open

Creates a new window and loads the specified document into it.

postMessage

8	3	9.5

Provides communication between two documents regardless of their location.

Prints the contents of the current window.

prompt

Displays a prompt dialog with a message, an input field, an OK and a Cancel button.

releaseEvents


	3

Stops capturing the specified events that was previously set by the captureEvents method.

removeEventListener

9

Removes the specified event handler from the current element that was registered earlier with the addEventListener method.

resizeBy

Resizes the browser window by the specified amount of pixels, relative to its current size.

resizeTo

Resizes the browser window to the specified size.

scroll

Scrolls the contents of the document window to the specified horizontal and vertical positions.

scrollBy

Scrolls the contents of the document window by the specified number of pixels.

scrollByLines

Scrolls the contents of the document vertically by the specified number of lines.

scrollByPages

Scrolls the contents of the document vertically by the specified number of pages.

scrollTo

Scrolls the contents of the document window to the specified horizontal and vertical positions.

setInterval

Starts a timer that periodically repeats the execution of the specified expression.

setTimeout

Starts a timer that executes a piece of code after the specified number of milliseconds have elapsed.

showHelp

Opens a HTML help (.chm or .hlp) file in an external application.

showModalDialog

	3

Creates a modal dialog and loads the specified document into it.

showModelessDialog

Creates a modeless dialog and loads the specified document into it.

sizeToContent

Fit the size of the current window to its contents.

stop

Stops the loading of the document's content. Same as clicking on the browser's stop button.

updateCommands

Updates the state of the specified commands.

onafterprint

Occurs when the browser has built the contents of the current document for printing or for the print preview.

onbeforeprint

Occurs when the browser starts to build the contents of the current document for printing or for the print preview.

onbeforeunload

Occurs before the browser unloads the document and provides a possibility to display a confirmation dialog, where the user can confirm whether he wants to stay or leave the current page.

onblur

Occurs when an element loses focus.

onchange

9

Occurs when the selection, the checked state or the contents of an element have changed. In some cases, it only occurs when the element loses the focus.

onclick

9

Occurs when the user clicks on an element.

ondblclick

9

Occurs when the user double clicks on an element.

onerror

Fires when a script error occurs.

onfocus

Occurs when an element receives focus.

onhashchange

8	3.6	10.6	5

Occurs when the hash subsection (begins with a '#' sign) of the current document's URL has changed.

onhelp

Occurs after the user has pressed the F1 key.

onkeydown

9

Occurs on an element that has the focus when a key is pressed down and occurs periodically until the key is released.

onkeypress

9

Occurs on an element that has the focus when a key is pressed down and occurs periodically until the key is released.

onkeyup

9

Occurs on an element that has the focus when the user releases a key.

onload

Occurs when an object has been loaded.

onmessage

8	3

Occurs when the postMessage method sends a message to the current window.

onmousedown

9

Occurs when the user presses a mouse button over an element.

onmousemove

9

Occurs when the user moves the mouse over the element.

onmouseout

9

Occurs when the user moves the mouse pointer out of the element.

onmouseover

9

Occurs when the user moves the mouse pointer into the element.

onmouseup

9

Occurs when the user releases a mouse button over an element.

onmousewheel

9

Occurs when the mouse wheel rolls.

onreset

9

Occurs on a form before it is reset.

onresize

Occurs when the size of an object has changed.

onscroll

Occurs when the contents of an element have been scrolled.

onselect

9

Occurs after some text has been selected in an element.

onsubmit

9

Occurs on a form element when the user clicks on a submit button in the form.

onunload

Occurs before the browser unloads the document.

Example HTML code 1:

This example shows how to open a child window and communicate between the opener and the child windows:

Code

childWindow.htm

<head>
    <script type="text/javascript">
        function OpenChildWindow () {
            window.open ("childWindow.htm", "OpenerTest", "width=300, height=200");
        }
    </script>
</head>
<body>
    First open a child window with this button:
    <button id="childOpener" onclick="OpenChildWindow ();">Open child window!</button>
    <br /><br />
    You can change the text color of the button with the selection list of the child window.
</body>

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8" />
    <title>Modeless window example</title>
    <script type="text/javascript">
        function ChangeOpener (selectTag) {
            var openerWindow = window.opener;
            var button = openerWindow.document.getElementById ("childOpener");
            button.style.color = selectTag.options[selectTag.selectedIndex].text;
        }
    </script>
<body>
    Change the color of the button in the opener window:
    <select onchange="ChangeOpener (this)">
        <option />black
        <option />red
        <option />blue
        <option />green
    </select>
</body>
</html>

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External links:

window (MSDN)
window (Mozilla Developer Center)
window (W3C)

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window object

Syntax:

Possible members:

Example HTML code 1:

External links:

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