对联广告关闭后网站所有图片就静止了，求高手帮忙看下

[mac_win]

代码如下
<!--对联广告开始-->
<SCRIPT language="JavaScript">
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*/}
//alert(diffY);
percent=.1*(diffY-lastScrollY);
if(percent>0)percent=Math.ceil(percent);
else percent=Math.floor(percent);
document.getElementById("leftDiv").style.top = parseInt(document.getElementById("leftDiv").style.top)+percent+"px";
document.getElementById("rightDiv").style.top = parseInt(document.getElementById("rightDiv").style.top)+percent+"px";
lastScrollY=lastScrollY+percent;
//alert(lastScrollY);
}
//下面这段删除后，对联将不跟随屏幕而移动。
window.setInterval("heartBeat()",1);
//-->
//关闭按钮
function close_left1(){
left1.style.visibility='hidden';
}
//function close_left2(){
//left2.style.visibility='hidden';
//}
function close_right1(){
right1.style.visibility='hidden';
}
//function close_right2(){
//right2.style.visibility='hidden';
//}
//显示样式
document.writeln("<style type=\"text\/css\">");
document.writeln("#leftDiv,#rightDiv{width:100px;height:100px;position:absolute;}");
document.writeln(".itemFloat{width:100px;height:auto;line-height:5px}");
document.writeln("<\/style>");
//以下为主要内容
document.writeln("<div id=\"leftDiv\" style=\"top:40px;left:5px\">");
//------左侧各块开始
//---L1
document.writeln("<div id=\"left1\" class=\"itemFloat\">");
document.writeln("<a target=_blank href=http://lng-expo.com/msg.php?id=204><img border=0 src=images/gas_2.jpg width=100 height=200></a>");
document.writeln("<br><a href=\"javascript:close_left1();\" title=\"关闭上面的广告\">×<\/a><br><br><br><br>");
document.writeln("<\/div>");
//---L2
//document.writeln("<div id=\"left2\" class=\"itemFloat\">");
//document.writeln("<a target=_blank href=http://www.farwayair.com.cn><img border=0 src=images/100_300.gif></a>");
//document.writeln("<br><a href=\"javascript:close_left2();\" title=\"关闭上面的广告\">×<\/a>");
//document.writeln("<\/div>");
//------左侧各块结束
document.writeln("<\/div>");
document.writeln("<div id=\"rightDiv\" style=\"top:40px;right:5px\">");
//------右侧各块结束
//---R1
document.writeln("<div id=\"right1\" class=\"itemFloat\">");
document.writeln("<a target=_blank href=http://www.igchina-expo.com/msg.php?id=210><img border=0 src=images/gas_1.jpg width=100 height=200></a>");
document.writeln("<br><a href=\"javascript:close_right1();\" title=\"关闭上面的广告\">×<\/a><br><br><br><br>");
document.writeln("<\/div>");
//---R2
//document.writeln("<div id=\"right2\" class=\"itemFloat\">");
//document.writeln("<a target=_blank href=http://www.ccair.net><img border=0 src=images/100_300_2.gif></a>");
//document.writeln("<br><a href=\"javascript:close_right2();\" title=\"关闭上面的广告\">×<\/a>");
//document.writeln("<\/div>");
//------右侧各块结束
document.writeln("<\/div>");
</SCRIPT>