I always end up leaving debug code in my pages for one reason or another. One of which is console.log() for the firebug extension. Now, if you leave this and a user opens your page on IE or something like that, they will get an error.
Put the following code into a JS file, like your base file. And it will check for the existence of console and avoid the problem.
if (!window.console) {
window.console = {};
window.console.log = function() {};
}