webpage - JavaScript at bottom/top of web page?

Question

I was just using the plugin "Yslow" for Mozilla Firefox, and it told me that I should put JavaScript at the bottom. I have heard this before but haven't really thought about it too much. Is there really an advantage in putting JavaScript at the bottom of a web page compared to the top?

Answer 1

It'll allow the web page to load visibly before executing JavaScript, which makes sense for things like Google Analytics, which don't need to happen before the page loads.

You may also want to look into things like jQuery, prototype, etc and attach to the "ready" handler, which executes JavaScript code after the DOM has been fully loaded, which is an appropriate place for much JavaScript code.