function regis()
    {
      window.location="register.jsp";
    }
    function login()
    {
      window.location="welcome.jsp";
    }
    function validate()
    {
      if(document.getElementById("userid").value=="")
       {
           alert("please enter userid");
           document.getElementById("userid").focus();
           return false;
       }
      if(document.getElementById("pass").value=="")
       {
           alert("please enter password");
           document.getElementById("pass").focus();
           return false;
       }
     }
	function PopupCenter(pageURL, title,w,h) 
		{
		var left = (screen.width/2)-(w/2);
		var top = (screen.height/2)-(h/2);
		var targetWin = window.open (pageURL, title, 'toolbar=no, location=no, directories=no, status=no, menubar=no, scrollbars=no, resizable=no, copyhistory=no, width='+w+', height='+h+', top='+top+', left='+left);
		}