Outputs a warning message to the Web Console.

Note: This feature is available in Web Workers.

Note: In Firefox, warnings have a small exclamation point icon next to them in the Web Console log.


console.warn(obj1 [, obj2, ..., objN]);
console.warn(msg [, subst1, ..., substN]);


obj1 ... objN
A list of JavaScript objects to output. The string representations of each of these objects are appended together in the order listed and output.
A JavaScript string containing zero or more substitution strings.
subst1 ... substN
JavaScript objects with which to replace substitution strings within msg. This gives you additional control over the format of the output.

See Outputting text to the console in the documentation of console for details.


Specification Status Comment
Console API
The definition of 'console.warn()' in that specification.
Living Standard Initial definition

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support Yes1248 Yes Yes
Substitution strings Yes Yes9101 ? ?
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support ? ? Yes4 ? ? ?
Substitution strings ? ? Yes9 ? ? ?

1. %c is not supported, %d will render as 0 when it is not a number

See also

Document Tags and Contributors

Last updated by: connorshea,