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console.warn

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.

Syntax

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

Parameters

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.
msg
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.

Specifications

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

Browser compatibility

Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari
Basic support (Yes) (Yes) 4.0 (2.0) 8 (Yes) (Yes)
Substitution strings ? (Yes) 9.0 (9.0) ? ? ?
Available in workers ? (Yes) 38.0 (38.0) ? ? ?
Feature Android Edge Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support ? (Yes) 4.0 (2.0) ? ? ?
Substitution strings ? (Yes) 9.0 (9.0) ? ? ?
Available in workers ? (Yes) 38.0 (38.0) ? ? ?

See also

© 2005–2017 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/console/warn