$signature = '我是个性签名[/happy][/happy][/happy]'
$part = '<img src="images/em/\\1.gif" align="absmiddle" />';
$from = '/\[\/(.*)\]/';
$out = preg_replace($from,$part,$signature);得出的结果不是  我是个性签名<img src="images/em/happy.gif" align="absmiddle" /><img src="images/em/happy.gif" align="absmiddle" /><img src="images/em/happy.gif" align="absmiddle" />而是 我是个性签名<img src="happiness][/happiness][/happiness.gif align="absmiddle" />求解决办法!