ใช้ header แล้วมีปัญหาเปิดเพจเลยใช้จาวา windows.location แล้วไม่ไป

	echo $topage;
	
	if($topage=="master"){ ?>
    	<script type="text/javascript">
			windows.location.href="master_page.php";
		</script>
 <?php  exit(0);}
 	elseif($topage=="admin"){ ?>
    	<script type="text/javascript">
			windows.location.href="admin_page.php";
		</script>
 <?php 	exit(0);}
 	else{ ?>
    	<script type="text/javascript">
			windows.location.href="register.php";
		</script>
  <?php	
  echo $topage;
  exit(0);}
	
	

	
	
	
	?>