If you understand jquery programing you can do:
You can easily select elements to perform manipulation.
You can easily create effect like show or hide elements, sliding transition, and so on.
You can easily create complex CSS animation with fewer lines of code.
You can easily manipulate DOM elements and their attributes.
You can easily implement Ajax to enable asynchronous data exchange between client and server.
You can easily traverse all around the DOM tree to locate any element.
You can easily perform multiple actions on an element with a single line of code.
You can easily get or set dimensions of the HTML elements.