织梦dedecms怎么在列表页和内容页调用自定义字段中的checkbox多选框的值

[field:sizes runphp=yes]
$arr = explode(',',@me);
$result = '';
for($index=0;$index<count($arr);$index++){
    $result .= "<span>$arr[$index]</span>";
}
@me = $result;
[/field:sizes]

{dede:field.sizes runphp=yes}
$arr = explode(',',@me);
$result = '';
for($index=0;$index<count($arr);$index++){
    $result .= "<span>$arr[$index]</span>";
}
@me = $result;
{/dede:field.sizes}

{dede:field name='sizes' runphp='yes'}
$a=explode(",",@me);
@me = "";
foreach($a as $k)
{
@me.="<span>$k</span>";
}
{/dede:field}