function  loginvalidate() 
{		
 if(isBlank(document.form1.username.value))
        {
                alert("Please Enter a valid UserName!");
                return false;
        }

  if (isBlank(document.form1.password.value)) 
        {
                alert("Please Enter a valid Password!");
                return false;
        }
         
        document.form1.action="loginpost.php";
        document.form1.submit();
}