...I'm a complete noob with Java.
Just a quick note; java != javascript.
And one last question: is it recommended to use jQuery / Javascript in your webpages?
Absolutely. Javascript makes your page come alive. A lot of the new HTML5 / CSS3 stuff duplicates javascript actions. When I'm building a page for a client I always try to use HTML5/CSS3 first, if I find that they don't fill the need I'll throw in some javascript.And one last question: is it recommended to use jQuery / Javascript in your webpages?