<script>
          $(document).ready(function(){
            $("#button").click(function(){
         if(diff1>31)
        {
        alert("You can't extend more than one month");
        }
         else
        {
        var jspcall = "thnks.jsp";
        window.location.href = jspcall;
        }
        });
});
 </script>
And here is my jsp code
                  Date date=edate;
       System.out.println("extend date" + date);
        java.sql.Date content = new java.sql.Date(date.getTime());
java.util.Date exp_date = new java.util.Date(content.getTime());
         java.util.Date cur_date = new java.util.Date();
         System.out.println(cur_date);
 long  diff= exp_date.getTime() - cur_date.getTime();
 long diff1=diff/(24 * 60 * 60 * 1000);
 %>
     <li>
    <button class="submit"> submit </button>
This all in same jsp page. Any other suggestion apart from this?