php join函数应用

$key = array();
$val = array();
foreach ($_POST as $k=>$v)
{
$key[] = '`'.strip_tags(mysql_real_escape_string(trim($k))).'`';
$val[] = "'".strip_tags(mysql_real_escape_string(trim($v)))."'";
}

$keys = join(",",$key);
$vals = join(",",$val);