1.
$(document).ready(function() {
2.
// put all your jQuery goodness in here.
3.
});

The $(document).ready() function has a ton of advantages over other ways of getting events to work. First of all, you don’t have to put any “behavioral” markup in the HTML. You can separate all of your javascript/jQuery into a separate file where it’s easier to maintain and where it can stay out of the way of the content. I never did like seeing all those “javascript:void()” messages in the status bar when I would hover over a link. That’s what happens when you attach the event directly inside an tag.

On some pages that use traditional javascript, you’ll see an “onload” attribute in the tag. The problem with this is that it’s limited to only one function. Oh yeah, and it adds “behavioral” markup to the content again. Jeremy Keith’s excellent book, DOM Scripting, showed me how to create an addLoadEvent function to a separate javascript file that allows for multiple functions to be loaded inside it. But it requires a fair amount of code for something that should be rather straightforward. Also, it triggers those events when the window loads, which leads me to another advantage of $(document).ready().
http://www.szcpost.com/2009/01/shenzhen-metro.html

to

document.write(“”);

this will remove mix content warning from IE 7 and 8
on https pages