PHP更新购物车数量(表单部分/PHP处理部分)

<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
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;
}
?>