mozilla

Console.log()

Non-standard
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.

Summary

Outputs a message to the Web Console.

Note: This feature is available in Web Workers.

Syntax

console.log(obj1 [, obj2, ..., objN]);
console.log(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.

Specification

Console Object API

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support (Yes) 4.0 (2.0) 8 (Yes) (Yes)
Substitution strings

(Yes)

28

%d - if negative value is passed
it will be rounded down
to the closest negative number
-0.1 becomes -1

9.0 (9.0)

10 - partial

%c - not supported
%d - will render as 0 when NaN

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

See also