The first thing you need to do is understand the difference between the server and the client.ASP.NET MVC lives on the server. MVC is a framework for serving up web requests. You can write MVC applications that use 0 lines of JavaScript or jQuery.The client-side JavaScript, specifically jQuery, is its own monster. jQuery provides shortcuts for working and manipulating the DOM. jQuery and JavaScript is independent of the server, and can be used with any type of web server, Microsoft stack or otherwise.The two are very closely related because there is a lot of functionality where constant communication between the server and the client, or pages that change as the user performs various actions, is almost necessary functionality in "modern" web applications.

Go to following link-http://www.ibm.com/developerworks/library/wa-jquerywebapps/

jQuery can be used in following scenarios:Apply CSS static or dynamic Calling functions on events Manipulation purpose Mainly for Animation effects