What is jQuery?

Since you've come to this page, you may already have a pretty good idea about what jQuery is, but to be on the safe side, here is a brief explanation. jQuery is a JavaScript framework, which purpose is to make it much easier to use JavaScript on your website. You could also describe jQuery as an abstraction layer, since it takes a lot of the functionality that you would have to write many lines of JavaScript to accomplish and wraps it into functions that you can call with a single line of code. It's important to note that jQuery does not replace JavaScript, and while it does offer some syntactical shortcuts, the code you write when you use jQuery is still JavaScript code.

With that in mind, you should be aware that you don't need to be a JavaScript expert to use jQuery. In fact, jQuery tries to simplify a lot of the complicated things from JavaScript, like AJAX calls and DOM manipulation, so that you may do these things without knowing a lot about JavaScript.

There are a bunch of other JavaScript frameworks out there, but as of right now, jQuery seems to be the most popular and also the most extendable, proved by the fact that you can find jQuery plugins for almost any task out there. The power, the wide range of plugins and the beautiful syntax is what makes jQuery such a great framework. Keep reading to know much more about it and to see why we recommend it.

Source:http://www.tutorialsdesk.com/2012/08/what-is-jquery.html