JQuery is simply a Java Framework which can add interactivity to webpages. With JQuery, you can add anmations and much more than you can imagine to your website. And the best of it is, it can be run on all browsers. It can be therefore necessary that one learns how to Programm and code JQuery.
Here is a list of sites where you can learn JQuery
Now you can start up learning JQuery today.
Hope this helped.