点击超级链接返回上一页
<a href="javascript:void(0)" onclick="javascript:window.history.go(-1);" class="lmenu">返回列表</a>
php自动跳转回上一页
echo "<Script Language='Javascript'>"; echo "alert('提示:管理员ID已存在,请重新输入!');"; echo "history.go(-1);"; echo "</Script>";