Web/JavaScript/Reference/Operators/Exponentiation assignment

The exponentiation assignment operator (**=) raises the value of a variable to the power of the right operand.

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Syntax

Operator: x **= y
Meaning:  x  = x ** y

Examples

Using exponentiation assignment

// Assuming the following variable
//  bar = 5

bar **= 2     // 25
bar **= 'foo' // NaN

Specifications

Specification

ECMAScript (ECMA-262)The definition of 'Assignment operators' in that specification.

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile						Server
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet	Node.js
Exponentiation assignment (`x **= y`)	Chrome Full support 52	Edge Full support 14	Firefox Full support 52	IE No support No	Opera Full support 39	Safari Full support 10.1	WebView Android Full support 51	Chrome Android Full support 52	Firefox Android Full support 52	Opera Android Full support 41	Safari iOS Full support 10.3	Samsung Internet Android Full support 6.0	nodejs Full support 7.0.0 Full support 7.0.0 Full support 6.5.0 Disabled' Disabled' From version 6.5.0: this feature is behind the `--harmony` runtime flag.

Legend

Full support: Full support
No support: No support
User must explicitly enable this feature.': User must explicitly enable this feature.