you have to keep an eye on version changes - for example, as the docs note, as of jQuery 1.3, .trigger()ed events bubble up the DOM tree, which is a fairly major change.
if you want, you can make sure that you always have the latest version just by calling
Code:
<script src="http://code.jquery.com/jquery-latest.js"></script>
or
Code:
<script src="http://code.jquery.com/jquery-latest.min.js"></script>
if that's what you're into