We're looking for a person or people to help audit MDN to find places we could speed up. Is this you or someone you know? Check out the RFP: https://mzl.la/2IHcMiE

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 Number object, toSource() returns the following string indicating that the source code is not available:

function Number() {
    [native code]

For instances of Number, toSource() returns a string representing the source code.

This method is usually called internally by JavaScript and not explicitly in web code.


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 AndroidOpera AndroidiOS SafariSamsung Internet
Basic support No No No Yes No No ?

See also

Document Tags and Contributors

 Last updated by: fscholz,