I've recently moved a site over to use the Google AJAX Libraries instead of hosting the library js files myself. At the moment I'm using the Google recommended approach:
<script type="text/javascript" src="http://www.google.com/jsapi?key=MYAPIKEY"></script>
<script type="text/javascript">google.load('jquery', '1.3.2');</script>
But it seems a little silly to me to include an extra JavaScript file, just so I can call another script file.
My question is, is there actually any advantage to calling these files via google.load() as opposed to simply including them via script tag like so:
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js"></script>
My main reasons for using the Google hosted libraries are the speed of their CDN/edge caching systems; am I still getting those benefits if I link directly to the file?
the main advantage for using the loader api is that you will prevent blocking by the browser when its doing the initial downloads. Browsers can only download between 2 & 10 things at a time so if there is blocking it will give bad user experience
Steve Souders and the Yahoo! Exceptional Performance team have done a lot of research into this to get faster websites. Nick Zakas (JavaScript guru) blogged about using Steve's ideas here