A good way to override the `console.log` function in the browser, Yet preserved the original functionality of the function. In this example I want to send any `console.log` call to my Node.js/Socket.io server.

consolelog.override.js

(function(){
    //saving the original console.log function
    var preservedConsoleLog = console.log;
 
    //overriding console.log function
    console.log = function() {
 
        //we can't just call to `preservedConsoleLog` function,
        //that will throw an error (TypeError: Illegal invocation)
        //because we need the function to be inside the
        //scope of the `console` object so we going to use the
        //`apply` function
        preservedConsoleLog.apply(console, arguments);
 
        //and lastly, my addition to the `console.log` function
        if(application.socket){
            application.socket.emit('console.log', arguments);
        }
    }
})();

Read more about it here: http://udidu.blogspot.co.il/2012/12/override-console-functions.html