//To set the innerHTML of <li class="item31">
// # is the ID select
// . is the class selector
$('.item31').html('My new HTML');
JQuery it's a very useful JS lib, learn it and it'll save u time =)
You can have jQuery + Mootols without conflict, or jQuery with Prototype without conflict, etc. Apart from the noConflict(), have you tried having all jQuery stuff (lib, plugs, code)loaded first, then the rest of js?
I tried jQuery instead of $ but the problem was i call the jquery.min.js file form the ajax.googleapis.com, i did it separately into my joomla directory, and then it worked with jQuery.noConflict(); and used jQuery instead of $ without any conflicting with mootools..