post 获取checkbox值

$str_tag="";
$s=$_POST['goods_server_name'];
for($i=0;$i<count($s);$i++){
if($i==0){
$str_tag = $s[$i];
}else{
$str_tag = $str_tag .",".$s[$i];
}
}
echo $str_tag;

<?php foreach($store as $v): ?>
<option value="<?php echo $v['shopid'] ;?>" <?php echo set_select('shopid',$v['shopid']); ?>>
<?php echo $v['shopname'] ;?>
</option>
<?php endforeach; ?>