Here is a good explanation:
http://stackoverflow.com/questions/3755606/what-does-the-exclamation-mark-do-before-the-function
– EdwardBAug 09 '14 at 10:54
1
It's a short-hand for self-invoking anonymous functions, it's same as `(function(){
// code
})();`
– MritunjayAug 09 '14 at 10:56