Also be careful how you execute the js on the page. For example if you do something like this:
(function(window, document, undefined){
var foo = document.getElementById("foo");
console.log(foo);
})(window, document, undefined);
This will return null because you’d be calling the document before it was loaded.
Better option..
(function(window, document, undefined){
// code that should be taken care of right away
window.onload = init;
function init(){
// the code to be called when the dom has loaded
// #document has its nodes
}
})(window, document, undefined);