弹出层（Div）屏蔽父窗口并且让父窗口变暗
<html><head><script> function locking(){ document.all.ly.style.display="block"; document.all.ly.style.width=document.body.clientWidth; document.all.ly.style.height=document.body.clientHeight; document.all.Layer2.style.display='block'; } function Lock_CheckForm(theForm){ document.all.ly.style.display='none'; document.all.Layer2.style.display='none'; return false; } </script></head><body> <img src="http://powereasy.net/skin/since07/images/sf_cms_banner1.jpg"> <p align="center"> <input type="button" value="系统锁定" onclick="locking()"> </p> <div id="ly" style="position: absolute; top: 0px; filter: alpha(opacity=60); background-color: #777; z-index: 2; left: 0px; display: none;"> </div> <!-- 浮层框架开始 --> <div id="Layer2" align="center" style="position: absolute; z-index: 3; left: expression((document.body.offsetWidth-540)/2); top: expression((document.body.offsetHeight-170)/2); background-color: #fff; display: none;" > <table width="540" border="0" cellpadding="0" cellspacing="0" style="border: 0 solid #e7e3e7; border-collapse: collapse"> <tr> <td style="background-color: #73A2d6; color: #fff; padding-left: 4px; padding-top: 2px; font-weight: bold; font-size: 14px;" height="27" valign="middle"> [ 警 告 ] </td> </tr> <tr> <td height="130" align="center"> <input type="button" value=" 确定 " onclick="Lock_CheckForm(this);"> </td> </tr> </table> </div> <!-- 浮层框架结束 --></body></html>