jQuery plug-ins not working with MVC 3?

1. Is the client getting the js file? 
2. If you’re using HTTPS and the js files are on a remote server, make sure it is an HTTPS endpoint. 
3.Test the js files in a standalone html file. If it works, try putting a cast around the jQuery script.

Example with jQuery UI:

<div id="progressbar"></div>

(function ($) {
    $(document).ready(function () {
            $("#progressbar").progressbar({ value: 37 });
        }
    });
} (jQuery));

This worked for me.