window object
[This documentation is preliminary and is subject to change.]
Represents an open window.
Standards information
There are no standards that apply here.
Remarks
You can use the window object to retrieve information about the state of the window. You also can use this object to gain access to the document in the window, to the events that occur in the window, and to other factors that affect the window.
You can apply any window property, method, or collection to any variable or expression that evaluates to a window object, regardless of how that window was created. Additionally, you can access all window properties, methods, and collections in the current window by using the property, method, or collection name directly—that is, without prefixing it with an expression that evaluates to the current window object. However, to help make more readable code and to avoid potential ambiguities, many authors use the window keyword when accessing window properties, methods, and collections for the current window. This keyword always refers to the current window.
Note The window's properties, methods, and collection names are reserved keywords and cannot be used as the names of variables or routines.
The following table lists pertinent information for some of the properties of the window object.
| Property | Method | Description |
|---|---|---|
| opener | open | The opener property is available only from a document opened using the window.open method. |
| parent, top | None | The parent and top properties are available for a window opened inside a frame or iframe. The two properties return the topmost parent and immediate parent, respectively. |
| parent, top | open | The parent and top properties are available for a window opened via the open method or as a dialog and returns the current window. |
| length | None | Regardless of how the window is opened, the length property returns the number of frames in a window. |
| dialogArguments, dialogHeight, dialogLeft, dialogTop, dialogWidth, returnValue | showModalDialog and showModelessDialog | These properties are available only for windows created using the two methods listed—showModalDialog and showModelessDialog |
Typically, the browser creates one window object when it opens an HTML document. However, if a document defines one or more frames (that is, contains one or more frame or iframe tags), the browser creates one window object for the original document and one additional window object for each frame. These additional objects are of the original window and can be affected by actions that occur in the original. For example, closing the original window causes all child windows to close. You can also create new windows (and corresponding window objects) using methods such as open, showModalDialog, and showModelessDialog.
In Windows CE, the document object is not available through scripting for a window object opened using the open method.
Examples
This example displays an alert for the current window.
alert("A simple message.")
This example checks whether the current window contains child windows and, if it does, displays the names of those child windows in a debugging console window (see F12 Developer Tools for more information).
if ( window.frames != null ) {
for ( i = 0; i < window.frames.length; i++ )
console.log("Child window " + i + " is named " + window.frames(i).name);
}
This example shows a simple event handler function for the window's onload event. In the absence of a "window" element, the body element hosts the following window object events: onblur, onbeforeunload, onfocus, onload, and onunload.
<body onload="console.log('Document is loaded!');">
Build date: 2/14/2012
Returns the instantaneous local date+time as a string. Applies to: window. Syntax: window.Date()
N.B. This is similar to the Date object (SEE Date Object) but does not include the UTC-Zone-mark.
- 7/27/2010
- Mr. Raymond Kenneth Petry
