function check_UP_fields() 
{
     var req = Inint_AJAX();
     req.onreadystatechange = function () { 
          if (req.readyState==4) {
               if (req.status==200) {
					if(req.responseText == 'success')
						window.location = 'index.php';
					else
						document.getElementById('UP_login_msg').innerHTML=req.responseText; //retuen value
               } 
          }
     };
	 var username = document.UP_Login.username.value;
	 var password = document.UP_Login.password.value;
	 var type	  = document.UP_Login.type.value;
     req.open("GET", "includes/codes/login_ajax.php?u="+username+"&p="+password+"&t="+type); //make connection
     req.setRequestHeader("Content-Type", "application/x-www-form-urlencoded;charset=utf-8"); // set Header
     req.send(null); //send value
}
.