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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).

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

Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
self
1
12
1
4
≤12.1
3
1
18
4
≤12.1
1
1.0

See also

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https://developer.mozilla.org/en-US/docs/Web/API/Window/self