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console: warn() method

The console.warn() method outputs a warning message to the Web console.

Note: This feature is available in Web Workers

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

Syntax

js

warn(obj1)
warn(obj1, /* …, */ objN)
warn(msg)
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.

Return value

None (undefined).

Specifications

Specification
Console Standard
# warn

Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
warn 1 12 4 8 10.5 3 4.4 18 4 11 1 1.0

See also

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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/console/warn