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debugger

The debugger statement invokes any available debugging functionality, such as setting a breakpoint. If no debugging functionality is available, this statement has no effect.

Syntax

debugger;

Examples

The following example shows code where a debugger statement has been inserted, to invoke a debugger (if one exists) when the function is called.

function potentiallyBuggyCode() {
    debugger;
    // do potentially buggy stuff to examine, step through, etc.
}

When the debugger is invoked, execution is paused at the debugger statement. It is like a breakpoint in the script source.

Paused at a debugger statement.

Specifications

Browser compatibility

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 IE mobile Opera Android iOS Safari
Basic support Yes Yes Yes Yes Yes Yes Yes

See also

© 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/debugger