SharePoint 2010 Broken Page Menu Ribbon (Keep on Loading)

My ribbon page menu suddenly stopped working this afternoon. Clicking the page menu gave me the loading icon without any progress.

After some investigation I found out that the code which I added this morning is the problem.

        String.prototype.startsWith = function(str){

            return (this.toLowerCase().indexOf(str) == 0);

        }

Apparently “startsWith” is a reserved word so changing the function name into another name fixed the problem.

A friend of mine told me “SharePoint keeps you young by forcing you to learn new stuffs almost everyday”.

And he is right J