lastScrollY=0;
function heartBeat(){
var diffY;
if (document.documentElement && document.documentElement.scrollTop)
diffY = document.documentElement.scrollTop;
else if (document.body)
diffY = document.body.scrollTop
else
{/*Netscape stuff*/}

percent=.1*(diffY-lastScrollY);
if(percent>0)percent=Math.ceil(percent);
else percent=Math.floor(percent);
document.getElementById("fleft").style.top=parseInt(document.getElementById("fleft").style.top)+percent+"px";
document.getElementById("fright").style.top=parseInt(document.getElementById("fright").style.top)+percent+"px";

lastScrollY=lastScrollY+percent;
}


lclose = "<div id=\"fleft\" style='left:4px;position:absolute;top:250px;z-index:9999999;'><div><a href=\"javascript:\" onclick=\"document.getElementById('fleft').style.display='none';\" style='left:0px;top:88px;;'><font color=\"#000000\">关闭</font></a></div>";

rclose = "<div id=\"fright\" style='right:4px;position:absolute;top:250px;z-index:9999999;'><div style='right:4px;position:absolute;top:-15px;'><a href=\"javascript:\" onclick=\"document.getElementById('fright').style.display='none';\"><font color=\"#000000\">关闭</font></a></div>";

/*fleft = "<a href=#><img src=images/expovolunteer090421.gif border=0></a></div>"; */
fleft  = "<a href=\"http://www.pdvolunteer.org.cn/view.php?nid=3834\" target=\"_blank\"><img src=\"./images/paper100531.jpg\" border=0></a></div>";

fright  = "<a href=\"http://www.pdvolunteer.org.cn/class.php?cid=161\" target=\"_blank\"><img src=\"./images/car090629.jpg\" border=0></a></div>";
document.write(lclose);
document.write(fleft);
document.write(rclose);
document.write(fright);
window.setInterval("heartBeat()",1);