ajax实现标签导航

   CreateXMLHttpRequest();   

   getObject(requestType+'_cnt').innerHTML = loadstatustext;
   xmlHttp.onreadystatechange = processRequestChange;
   xmlHttp.open("GET", url, true);
   xmlHttp.setRequestHeader("If-Modified-Since","0");
   xmlHttp.send(null);  
}

function processRequestChange(){
   // only if xmlHttp shows "complete"
   if (xmlHttp.readyState == 4){
      // only http 200 to process
      if (window.location.href.indexOf("http")==-1 || xmlHttp.status == 200){
         newsstring = xmlHttp.responseText;
         //inject centent to tab-pane
            shownews(requestType,newsstring);
      }
   }
}

function shownews(requestType,newsstring){
//<![CDATA[
    responsecont = getObject(requestType+'_cnt');
    responsecont.innerHTML = newsstring;
//]]>
}

function TabNews(tagid,x){
    for (var i=1;i<=7;i+=2) {
         if (i == x) {
            getObject(tagid+i).className="tabactive"+i;
            if(i!=1){
               getObject(tagid+(i-1)).style.display="none";               
               if(i!=7){
                  getObject(tagid+(i+1)).style.display="none";
               }                 
            }
            if(i==1){
               getObject(tagid+"2").style.display="none";
            } 
            try{