debugger

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

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

js
debugger;

Examples

Using the debugger statement

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

js
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.

A browser with developer tools open to the debugger panel showing how execution is paused at the debugger statement to allow close inspection of variables, scopes, events, etc.

Specifications

Specification
ECMAScript Language Specification
# sec-debugger-statement

Browser compatibility

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See also