ช่วยดูโค้ด redirect ไปยังเพจต่างๆ หลังจากการ login หน่อยครับ ใช้ jquery (ต้องการแบ่งสิทธิการเข้าถึง)

// Preload Images
img1 = new Image(16, 16);  
img1.src="images/spinner.gif";

img2 = new Image(220, 19);  
img2.src="images/ajax-loader.gif";

// When DOM is ready
$(document).ready(function(){

// Launch MODAL BOX if the Login Link is clicked
$("#login_link").click(function(){
$('#login_form').modal();
});

// When the form is submitted
$("#status > form").submit(function(){  

// Hide 'Submit' Button
$('#submit').hide();

// Show Gif Spinning Rotator
$('#ajax_loading').show();

// 'this' refers to the current submitted form  
var str = $(this).serialize();  

// -- Start AJAX Call --

$.ajax({  
    type: "POST",
    url: "do-login.php",  // Send the login info to this page
    data: str,  
    success: function(msg){  
   
$("#status").ajaxComplete(function(event, request, settings){  
 
 // Show 'Submit' Button
$('#submit').show();

// Hide Gif Spinning Rotator
$('#ajax_loading').hide();  

 if(msg == 'OK') // LOGIN OK?
 {  
 var login_response = '<div id="logged_in">' +
	 '<div style="width: 350px; float: left; margin-left: 70px;">' + 
	 '<div style="width: 40px; float: left;">' +
	 '<img style="margin: 10px 0px 10px 0px;" align="absmiddle" src="images/ajax-loader.gif">' +
	 '</div>' +
	 '<div style="margin: 10px 0px 0px 10px; float: right; width: 300px;">'+ 
	 "You are successfully logged in! <br /> Please wait while you're redirected...</div></div>";  

$('a.modalCloseImg').hide();  

$('#simplemodal-container').css("width","500px");
$('#simplemodal-container').css("height","120px");
 
 $(this).html(login_response); // Refers to 'status'

// After 3 seconds redirect the 
setTimeout('go_to_private_page()', 3000); 
 }  
 else // ERROR?
 {  
 var login_response = msg;
 $('#login_response').html(login_response);
 }  
      
 });  
   
 }  
   
  });  
  
// -- End AJAX Call --

return false;

}); // end submit event

});

function go_to_private_page()
{
window.location = 'admin/index.php'; // ผมต้องการแก้ตรงนี้ครับ ถ้าเป็น user ธรรมดาให้ไป user/index.php
}

<?php
session_start();

if($_POST['action'] == 'user_login')
{
$username = $_POST["username"];
$password = $_POST["password"];

$sql = "select * from member as m, classmember as c where m.username = '$username' and m.password = '$password' and m.classid = c.classid";
$result = mysql_query($sql);
$rows = mysql_fetch_array($result);
$user = $rows["username"];
$pass = $rows["password"];
$class = $rows["classname"];
$firstname = $rows["firstname"];
$lastname = $rows["lastname"];
if(isset($user))
{
$_SESSION["user"] = $user;
$_SESSION["password"] = $pass;
$_SESSION["firstname"] = $firstname;
$_SESSION["lastname"] =  $lastname;
$_SESSION["class"] = $class;

			if($_POST['remember_me'])
			{
			// set the cookies for 1 month

			setcookie ("remember_me", true, (time() + TIME_DIFF) + (3600 * 24 * 30));
			setcookie ("info", $user_id.','.md5($password), (time() + TIME_DIFF) + (3600 * 24 * 30));
			}
	        echo 'OK'; // this response is checked in 'process-login.js'
	

}
	else 
	{
    $auth_error = '<div id="notification_error">The login info is not correct.</div>';

    echo $auth_error;
	}
}

?>

<!-- jqyrey login -->					
<div id="login_form" style='display:none'>
	<div id="status" align="left">
	<center>
	<h1><img src="images/key.png" align="absmiddle">&nbsp;LOGIN</h1> 
	<div id="login_response"><!-- spanner -->
	</div> <!--end div login_respone-->
	</center>
	<form id="login" action="javascript:alert('success!');">
		<input type="hidden" name="action" value="user_login">
		<input type="hidden" name="module" value="login">
		<label>username</label><input type="text" name="username"><br />  
		<label>Password</label><input type="password" name="password"><br />  
		<label>&nbsp;</label><input value="Login" name="Login" id="submit" class="big" type="submit" />
		<div id="ajax_loading">
			<img align="absmiddle" src="images/spinner.gif">&nbsp;Processing...	
  		</div> <!--end div ajax_loading -->
	</form>
	</div> <!--end div status -->
</div> 
<!--end jquery login -->