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This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.

The toSource() method returns a string representing the source code of the object.



Return value

A string representing the source code of the object.


The toSource method returns the following values:

  • For the built-in Function object, toSource() returns the following string indicating that the source code is not available:
    function Function() {
        [native code]
  • For custom functions, toSource() returns the JavaScript source that defines the object as a string.

This method is usually called internally by JavaScript and not explicitly in code. You can call toSource while debugging to examine the contents of an object.


Not part of any standard. Implemented in JavaScript 1.3.

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support No No Yes No No No
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidIE mobileOpera AndroidiOS Safari
Basic support No No No Yes No No No

See also

Document Tags and Contributors

 Last updated by: fscholz,