Add JQuery Reference

   <script type="text/javascript"

            src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.7.1.min.js">    

    </script>

    <script type="text/javascript">

        if (typeof jQuery == 'undefined') {

            document.write(unescape("%3Cscript src='Scripts/jquery-1.4.1.min.js'"

                                + "type='text/javascript'%3E%3C/script%3E"));

        }

    </script>