window.self

The Window.self read-only property returns the window itself, as a WindowProxy. It can be used with dot notation on a window object (that is, window.self) or standalone (self). The advantage of the standalone notation is that a similar notation exists for non-window contexts, such as in Web Workers. By using self, you can refer to the global scope in a way that will work not only in a window context (self will resolve to window.self) but also in a worker context (self will then resolve to WorkerGlobalScope.self).

Syntax

var w = window.self;  // w === window

Example

Uses of window.self like the following could just as well be replaced by window.

if (window.parent.frames[0] != window.self) {
    // this window is not the first frame in the list
}

Furthermore, when executing in the active document of a browsing context, window is a reference to the current global object and thus all of the following are equivalent:

var w1 = window;
var w2 = self;
var w3 = window.window;
var w4 = window.self;
// w1, w2, w3, w4 all strictly equal, but only w2 will function in workers

Specifications

Specification	Status	Comment
WHATWG HTML Living Standard The definition of 'Window.self' in that specification.	Living Standard	No difference from the latest snapshot HTML5.1
HTML5.1 The definition of 'Window.self' in that specification.	Working Draft	No difference from the HTML5
HTML5 The definition of 'Window.self' in that specification.	Recommendation	First snapshot containing the definition of Window.self.

Browser compatibility

See also

• Its Worker equivalent, WorkerGlobalScope.self.