jquery is what they call a javascript base library. it adds syntax to the javascript language to ease working with the DOM (your page as it runs in a browser), and adds plugins (HTML + jquery-based js) that perform functionality for you. see jquery.com ajaxrain.com
JQuery is a Java script framwork in which many functions are already written as classes and for having rapid javascript development. the Object oriented structure of it enables expanding the classes so that you dont need to invent the wheel again and again for same purposes. And is cool
An article I found points this out. jQuery is not different from JavaScript, it IS written in JavaScript. jQuery does not include any foreign code that is NOT Javascript. It is just a much more clever use of the language. "What is jQuery" http://www.authenticsociety.com/blog/WhatisjQuery_Part1