Javascript Console.log Not working in Chrome, or Firefox

I just came across this problem after a Firefox update and managed to fix it. Here's the code that caused the problem:

/* IE fix that allows me to still log elsewhere */if (typeof(console)=="undefined") {    var console = {        output: null,        log: function (str) {            // we can't emulate the console in IE, but we can cache what's output            // so that IE users can get it via console.output            if (!this.output) this.output = new Array();            this.output.push(new String(str));        }    };    window.console = console;}

In the previous version of FireFox, "var console;" wouldn't get executed. Now it seems to have added some sort of branching/prediction mechanism. Seeing that I may define a variable called console with global scope, it disables window.console.

I fixed this issue by renaming var console; to var cons;

/* IE fix that allows me to still log elsewhere */if (typeof(console)=="undefined") {    var cons = {        output: null,        log: function (str) {            // we can't emulate the console in IE, but we can cache what's output            // so that IE users can get it via console.output            if (!this.output) this.output = new Array();            this.output.push(new String(str));        }    };    window.console = cons;}

I still need to test this to make sure it does what I expect in IE, though. I just need to find a copy of IE without a console (I think 9 or below).

I just wish that Firefox would tell you what line of what script disabled the console - that would be nice.

I had the same issue with a Magento e-commerce site (version 1.6.2.0).

I fixed it commenting the following lines in /js/varien/js.js:637

if (!("console" in window) || !("firebug" in console)){    var names = ["log", "debug", "info", "warn", "error", "assert", "dir", "dirxml",    "group", "groupEnd", "time", "timeEnd", "count", "trace", "profile", "profileEnd"];    window.console = {};    for (var i = 0; i < names.length; ++i)        window.console[names[i]] = function() {}}

This fix is only (obviously) for Magento sites.

Turns out the theme developer had added firebug lite to the theme without me knowing. Turning it off fixed the problem.