เกี่ยวกับ code ตะกร้าสินค้าครับ ต้องการให้สั่งซื้อสินค้าเสร็จแล้วให้มัน refresh ตะกร้าสินค้าคับ ไม่ให้มันจำ session ตัวเดิม

<?
	session_start();
	include('config.inc.php');
	session_register("cart");
	if($_SESSION['ID_User'] == "")
	{
		echo "<script language='javascript'>alert('Please Login');history.back();</script>";
		exit();
	}
	

	$strSQL = "SELECT * FROM register WHERE ID_User = '".$_SESSION['ID_User']."' ";
	$objQuery = mysql_query($strSQL);
	$objResult = mysql_fetch_array($objQuery);
	
	if($_REQUEST['act']=='add' && !empty($_REQUEST['ID_Product']))
	{
		if(isset($_SESSION['cart'][$_REQUEST['ID_Product']]))
		{
			$_SESSION['cart'][$_REQUEST['ID_Product']]++;
		}
		else
		{
			$_SESSION['cart'][$_REQUEST['ID_Product']]=1;
		}
	}
	
	if($_REQUEST['act']=='remove' && !empty($_REQUEST['ID_Product']))
	{
		unset($_SESSION['cart'][$_REQUEST['ID_Product']]);
	}
	
	if($_REQUEST['act']=='update')
	{
		foreach($_POST['qty'] as $_SESSION['ID_Product']=>$_SESSION['qty'])
		{
			$_SESSION['cart'][$_SESSION['ID_Product']]=$_SESSION['qty'];
		}
	}
?>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
	<form id="frmcart" name="frmcart" method="post" action="?act=update">
  <table width="600" border="1" align="center">
  <tr>
  <td>Cart</td>
  </tr>
  <tr>
  <td>Product</td>
  <td width="117">Price</td>
  <td width="25">Unit</td>
  <td width="42">include</td>
  <td width="51">Remove</td>
  </tr>
  
 <?
 	$total=0;
	if(!empty($_SESSION['cart']))
	{
		foreach($_SESSION['cart'] as $_SESSION['ID_Product']=>$_SESSION['qty'])
		{
			
		$sql = "SELECT * FROM product where ID_Product = '".$_SESSION['ID_Product']."' ";
		$query = mysql_query($sql) or die ("error=$sql");
		$objResult = mysql_fetch_array($query);
		$_SESSION['P_Price'] = $objResult['P_Price'];
		$sum = $_SESSION['P_Price']*$_SESSION['qty'];
		$_SESSION['total'] += $sum;
		
	
	if($_SESSION['total']>=10000)
	{
		$sum1 = $_SESSION['total']*0.05;
		$sum2 = $_SESSION['total'] - $sum1;
		
	}	
	
  ?>
  <tr>
  	<td width="334"><?=$objResult["P_name"]?></td>
    <td width="46" align="right"><?=$_SESSION['P_Price']?></td>
    <td width="57" align="right">
    <input type="text" name="qty[<?=$_SESSION['ID_Product']?>]" value="<?=$_SESSION['qty']?>" size="2" />
    </td>
    <td width="93" align="right"><?=$sum?></td>
    <td><a href="order.php?ID_Product=<?=$_SESSION['ID_Product']?>&act=remove">remove</td>
   </tr>
   
   <?
   }
   ?>
   <tr>
   	<td>total</td>
    <td><?=$_SESSION['total']?></td>
   </tr>
   <tr>
   	<td>ส่วนลด 5% เมื่อซื้อครบ 10000  บาท</td>
    <td><?=$sum1?></td>
   </tr>
   <tr>
   	<td>ราคาสุทธิ์</td>
    <td><?=$sum2?></td>
   </tr>
   <tr>
   	<td><a href="user_page.php?id=2">BACK TO PRODUCT</a></td>
    <td>
    <input type="submit" name="button" id="button" value="update" />
    <input type="button" name="submit2" value="Checkout" onclick="window.location='order3.php';" />
    </td>
   </tr>
   
  <?
  }else
  {
  echo "NO CART";
  }
  ?>
  </table>
  </form>

<?
	session_start();
	include('config.inc.php');
	session_register("cart");

?>
<form id="cart1" name="cart1" method="post" action="process.php">
<table align="center" class="square" width="600" border="1">
<tr>
<td width="1400">สั่งซื้อสินค้า</td>
</tr>
<tr>
<tr>
  <td>Product</td>
  <td width="117">Price</td>
  <td width="25">Unit</td>
  <td width="42">include</td>
</tr>

<?
 $total=0;
 foreach($_SESSION['cart'] as $ID_Product=>$qty)
		{
		$sql = "SELECT * FROM product where ID_Product=$ID_Product";
		$query = mysql_query($sql) or die ("error=$sql");
		$objResult = mysql_fetch_array($query);
		$sum = $objResult['P_Price']*$qty;
		$total += $sum;
		
		
	if($_SESSION['total']>=10000)
	{
		$sum1 = $_SESSION['total']*0.05;
		$_SESSION['sum2'] = $_SESSION['total'] - $sum1;
		
	}	
  ?>
  <tr>
  	<td width="334"><?=$objResult["P_name"]?></td>
    <td width="46" align="right"><?=$objResult["P_Price"]?></td>
    <td width="57" align="right"><?=$qty?></td>
    <td width="93" align="right"><?=$sum?></td>
    </tr>
    
    <?
	}
	?>
    
	<tr>
   	<td>total</td>
    <td><?=$total?></td>
   </tr>
   <tr>
   	<td>ส่วนลด 5% เมื่อซื้อครบ 10000  บาท</td>
    <td><?=$sum1?></td>
   </tr>
   <tr>
   	<td>ราคาสุทธิ์</td>
    <td><?=$_SESSION['sum2']?></td>
   </tr>
   
   <tr>
   <td align="center" bgcolor="#cccccc" >
   <input type="submit" name="submit2" value="ยืนยัน" onclick="return confirm('ยืนยันการสั่งสินค้า')" />
   </td>
   </tr>
   </table>
   </form>
   

<?
	session_start();
	include('config.inc.php');
	session_register("cart");
	
date_default_timezone_set("Asia/Bangkok");

include("config.inc.php");


foreach($_SESSION['cart'] as $_SESSION['ID_Product']=>$_SESSION['qty'])
		{
$strSQL = "INSERT INTO bill2 ";
$strSQL .="(OrderDate,ID_User,Price,discount) ";
$strSQL .="VALUES ";
$strSQL .="('".date("Y-m-d H:i:s")."','".$_SESSION["ID_User"]."','".$_SESSION['total']."','".$_SESSION['sum2']."') ";
$objQuery = mysql_query($strSQL);

	}
	
$strID_Buy = mysql_insert_id();

 foreach($_SESSION['cart'] as $_SESSION['ID_Product']=>$_SESSION['qty'])
		{
$strSQL = "INSERT INTO bill ";
$strSQL .="(P_Number2,ID_Product,ID_Buy) ";
$strSQL .="VALUES ";
$strSQL .="('".$_SESSION['qty']."','".$_SESSION["ID_Product"]."','".$strID_Buy."') ";
$objQuery = mysql_query($strSQL);
		}

if($objQuery)
{
	include("config.inc.php");


 		$total=0;
		
		//echo '<pre>', print_r($_SESSION['cart'], true), '</pre>';
		  
 foreach($_SESSION['cart'] as $_SESSION['ID_Product']=>$_SESSION['qty'])
		{
		$sql = "SELECT * FROM product where ID_Product = '".$_SESSION['ID_Product'][$i]."' ";
		$query = mysql_query($sql) or die ("error=$sql");
		$objResult = mysql_fetch_array($query);
		$_SESSION['P_Price'] = $objResult['P_Price'];
		$sum = $_SESSION['P_Price']*$_SESSION['qty'];
		$_SESSION['total'] += $sum;
		
	
	if($_SESSION['total']>=10000)
	{
		$sum1 = $_SESSION['total']*0.05;
		$_SESSION['sum2'] = $_SESSION['total'] - $sum1;
		
	}	
	
	$strSQL = "Update product Set P_Number = P_Number - '".$_SESSION['qty']."' WHERE ID_Product = '".$_SESSION['ID_Product']."' ";
	$objQuery = mysql_query($strSQL);
	
		}
	}
	mysql_close();
	
	
	header("location:finish_order2.php?ID_Buy=".$strID_Buy);
  	 /*echo "<script language=\"JavaScript\" type=\"text/JavaScript\">alert('สั่งซื้อสินค้าเรียบร้อยแล้วครับ') </script> ";
		echo"<meta http-equiv='refresh' content='0;url=finish_order.php?ID_Buy='.$strID_Buy>";
		exit();	 */
	
	
?>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />

<font color="#FF0000" size="4">สั่งซื้อสินค้าเสร็จสิ้นแล้ว</font><br><br><br>

<a href="show_id_buy2.php?ID_Buy=<?=$_GET["ID_Buy"];?>"><img src="img/print.png" width="50" height="50" /><font color="#000000" size="3">พิมพ์ใบเสร็จสั่งซื้อ</font></a>