PHP正则表达式如何提取HTML标签属性值？

$re = '/onw+=(['"]).*?/m';$str = '<strong style="white-space: normal;" class="123" onload="asdasdas()">&nbsp</strong><div class="ccc">aaaaa</div><p style="white-space: normal;">bbbbb</p><strong class="123" style="white-space: normal;" onload="asdasdas()">12313123&nbsp</strong><strong onload='asdasdas()'>eeeeee&nbsp</strong><a href="http://www.xxx.com" target="_blank" class="aaaa">链接链接</a><p>ffff</p>';$subst = '';$result = preg_replace($re, $subst, $str);echo "替换的结果是 ".$result;