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.

Specifications

Specification	Status	Comment
ECMAScript 2017 Draft (ECMA-262) The definition of 'Debugger statement' in that specification.	Draft
ECMAScript 2015 (6th Edition, ECMA-262) The definition of 'Debugger statement' in that specification.	Standard
ECMAScript 5.1 (ECMA-262) The definition of 'Debugger statement' in that specification.	Standard	Initial definition
ECMAScript 3rd Edition (ECMA-262) The definition of 'Debugger statement' in that specification.	Standard
ECMAScript 1st Edition (ECMA-262) The definition of 'Debugger statement' in that specification.	Standard	Only mentioned as reserved word.

Browser compatibility

See also

• Debugging JavaScript
• The Debugger in the Firefox Developer Tools