console.warn()

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

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