PHP 更新购物车数量

表单部分：

<form action="?action=edit_num" method="post" name="car<?php $c_rs['id'];?>" id="car<?php $c_rs['id'];?>">
<input name="suliang[<?php echo $c_rs['sp_id'];?>]" type="text" id="suliang[<?php echo $c_rs['sp_id'];?>]" value="<?php echo $c_rs['suliang'];?>"/>
<input type="submit" name="button" id="button" value="更新购物车"  />
</form>

PHP 处理部分：

<?php
require 'config.inc.php';
require 'checklogin.php';
$username = $_SESSION['username'];

$action = $_GET['action'];
switch ($action) {
	case "edit_num":
	
		$arr = $arr = $_POST['suliang'];
		foreach($arr as $key=>$value){
    		$sqlgx = "update `cartemp` set suliang='$value' where username='".$username."' and flag=0 and sp_id='".$key."'";
			mysql_query($sqlgx, $conn);
			echo "<script>location.href='shopcat.php'</script>";
		}
		break;
	
    case "null":
        $null_sql = "delete from `cartemp` where username='$username' and flag=0 ";
        mysql_query($null_sql, $conn);
        echo "<script>location.href='shopcat.php'</script>";
        break;
    
    case "del":
        $id = $_GET['id'];
        $del_sql = "delete from `cartemp` where id=$id";
        mysql_query($del_sql, $conn);
        echo "<script>location.href='shopcat.php'</script>";
        break;
}
?>