The break statement terminates the current loop, switch
, or label
statement and transfers program control to the statement following the terminated statement.
break [label];
label
switch
, this is required.The break
statement includes an optional label that allows the program to break out of a labeled statement. The break
statement needs to be nested within the referenced label. The labeled statement can be any block
statement; it does not have to be preceded by a loop statement.
The following function has a break
statement that terminates the while
loop when i
is 3, and then returns the value 3 * x
.
function testBreak(x) { var i = 0; while (i < 6) { if (i == 3) { break; } i += 1; } return i * x; }
The following code uses break
statements with labeled blocks. A break
statement must be nested within any label it references. Notice that inner_block
is nested within outer_block
.
outer_block: { inner_block: { console.log('1'); break outer_block; // breaks out of both inner_block and outer_block console.log(':-('); // skipped } console.log('2'); // skipped }
The following code also uses break
statements with labeled blocks but generates a Syntax Error because its break
statement is within block_1
but references block_2
. A break
statement must always be nested within any label it references.
block_1: { console.log('1'); break block_2; // SyntaxError: label not found } block_2: { console.log('2'); }
Specification | Status | Comment |
---|---|---|
ECMAScript 1st Edition (ECMA-262) | Standard | Initial definition. Unlabeled version. |
ECMAScript 3rd Edition (ECMA-262) | Standard | Labeled version added. |
ECMAScript 5.1 (ECMA-262) The definition of 'Break statement' in that specification. | Standard | |
ECMAScript 2015 (6th Edition, ECMA-262) The definition of 'Break statement' in that specification. | Standard | |
ECMAScript Latest Draft (ECMA-262) The definition of 'Break statement' in that specification. | Draft |
Feature | Chrome | Edge | Firefox | Internet Explorer | Opera | Safari |
---|---|---|---|---|---|---|
Basic support | Yes | Yes | Yes | Yes | Yes | Yes |
Feature | Android webview | Chrome for Android | Edge mobile | Firefox for Android | Opera Android | iOS Safari | Samsung Internet |
---|---|---|---|---|---|---|---|
Basic support | Yes | Yes | Yes | Yes | Yes | Yes | ? |
© 2005–2018 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/break