10秒自动关闭层广告

<SCRIPT LANGUAGE="JavaScript">
<!--
//10秒自动关闭
setTimeout("closeAd()",20000);

function closeAd()
{
   document.getElementById("Adv_float").style.visibility="hidden";
}

//-->
        </SCRIPT>

<div id="Adv_float" class="div">
<TABLE WIDTH=377 BORDER=0 CELLPADDING=0 CELLSPACING=0>
 <TR>
  <TD>
   <IMG onclick="closeAd()" alt="关闭" SRC="adv/banner_1.gif" WIDTH=377 HEIGHT=35  style="cursor: hand;"></TD>
 </TR>
 <TR>
  <TD>
   <a href="#" target="_bank"><IMG SRC="adv/banner_2.gif" WIDTH=377 HEIGHT=282 border="0"></a></TD>
 </TR>
</TABLE>
</div>