Access window.console after overwrite

Question

Is it possible to somehow access to console.log after it gets overwritten?

window.console = { log: function (msg) { alert(msg); }, /* etc... */ };

Would be it be possible to regain the original console.log functionality?

Answer 1

Edit (2017-04-08): This advise is outdated, in Firefox 52 and Chrome 57 console is no longer defined on the window prototype and deleting it will really delete it.

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At least with the console object defined by Firefox and Chrome, you can simply delete the overwritten property to restore the original one:

window.console = {};
delete window.console;
window.console.log("This works!");

This works as if the console property were defined on the prototype of the window object - except that it isn't, the browsers are doing some magic here.

Answer 2

You can back up the console before overwriting it.

var oldConsole = window.console;
window.console = { log:function(msg){alert(msg)} //...};

Then you can use the oldConsole variable.

oldConsole.log('test');

If you can't back it up, you can create an iFrame, and then steal the console from there (this may not work in all browsers):

var i = document.createElement('iframe');
i.style.display = 'none';
document.body.appendChild(i);
window.console = i.contentWindow.console;

Demo: http://jsfiddle.net/jcG7E/2