修改一个定时切换的特效JS

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<style type="text/css">
/*样式，必须*/
.SplitShowContent{display: none;}
.show{display: block;}
.divChangeGroup{}
</style>
</head><body>这段代码在DIV里放JS代码会溺出，导致不切换卡住，能否防止JS广告溺出呢？最好再重新写个简短精简， 谢谢了！！！<script type="text/javascript">      function change(id){
        var container=document.getElementById(id);
        var firstDivChild=null;
        var curDivChild=null;
        var nextDivChild=null;
        for(var i=0;i<container.childNodes.length;i++){
            var obj=(container.childNodes)[i];
            if(obj.nodeType==1){
                if(obj.tagName.toLowerCase()=='div'){
                    if(firstDivChild==null)
                        firstDivChild=obj;
                    var cla=obj.className;
                    if((/[\w]*show[\w]*/).test(cla)){
                        curDivChild=obj;
                        continue;
                    }
                    if(curDivChild!=null && nextDivChild==null){
                        nextDivChild=obj;
                    }
                }
            }
        }
        if(nextDivChild==null)
            nextDivChild=firstDivChild;
        curDivChild.className=curDivChild.className.replace(/show/g,"");
        nextDivChild.className+= "show";
    }
    function changeDivContent(){
        for(var i=0;i<setting.target.length;i++){
            change(setting.target[i]);
        }
    }    
    var setting=new Object();
    
    window.onload=function(){
        var divs=document.getElementsByTagName('div');
        setting.speed=520;
        setting.target=new Array();
        for(var i=0;i<divs.length;i++){
            if((divs[i]).className=='divChangeGroup')
               setting.target.push((divs[i]).id);  
        }
        window.setInterval(changeDivContent,setting.speed);
    }
</script><div id="Div899" class="divChangeGroup"><div class="SplitShowContent show">
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<script type="text/javascript"><!--
google_ad_client = "pub-3553298197128602";
google_ad_slot = "3842766146";
google_ad_width = 468;
google_ad_height = 60;
//-->
</script>
<script type="text/javascript"
src="http://pagead2.googlesyndication.com/pagead/show_ads.js"> 
</script>
</div>
<div class="SplitShowContent">
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<script type="text/javascript"><!--
google_ad_client = "pub-3553298197128602";
google_ad_slot = "3842766146";
google_ad_width = 468;
google_ad_height = 60;
//-->
</script>
<script type="text/javascript"
src="http://pagead2.googlesyndication.com/pagead/show_ads.js"> 
</script>
</div>
</div><div id="Div900" class="divChangeGroup"><div 
class="SplitShowContent show">
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</div><div class="SplitShowContent">
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</div>
</div>
</body>
</html>