Ajax标签导航效果(仿网易首页)

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function getObject(objectId) {
     if(document.getElementById  document.getElementById(objectId)) {
    // W3C DOM
       return document.getElementById(objectId);
     } 
     else if (document.all  document.all(objectId)) {
    // MSIE 4 DOM
       return document.all(objectId);
     } 
     else if (document.layers  document.layers[objectId]) {
    // NN 4 DOM.. note: this won't find nested layers
       return document.layers[objectId];
     } 
     else {
       return false;
    }
} 

var responsecont;
var xmlHttp;
var requestType;
var newsstring;
var ajccache=new Object();//缓存已访问的数据页面
var url;
var MouseDelayTime=150;//鼠标感应延迟
var waitInterval;

function CreateXMLHttpRequest(){
   // Initialize Mozilla XMLHttpRequest object
   if (window.XMLHttpRequest){
       xmlHttp = new XMLHttpRequest();
   } 
   // Initialize for IE/Windows ActiveX version
   else if (window.ActiveXObject) {
       try{
            xmlHttp = new ActiveXObject("Msxml2.XMLHTTP.3.0");
       } 
       catch (e){
            try{
                xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
            }
            catch (e){newsstring = "div class='loading'>Loading rquest content fail, Please try it again latter.../div>";}
       }
   }
}

function getnews(tagid,x){
   url = "tab/"+tagid+'_'+x+'.html';
//   var loadstatustext="div class='loading'>img src='images/loading.gif' /> Loading request content, please wait.../div>";
   requestType = tagid;


if(ajccache[url]==null){
   CreateXMLHttpRequest();   

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

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);
            ajccache[url]=newsstring;    //把已访问的数据缓存下来
      }
   }
}

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{            
               getnews(tagid,i);
            }
            catch(e){
               alert(e);
            }  
        }
        else
        {
            getObject(tagid+i).className="";            
            if(i!=7){
               getObject(tagid+(i+1)).style.display="block";
            }             
        }         
   }
}

var idn;

function aet(objid,tagid,etp){    //为LI加上事件    objid：容器ID  tagid：组别   etp：触发类型 0-onmouseover 1-onclick
    var iif=0;
    var lis=objid.getElementsByTagName('li');
    requestType=tagid;
    url = "tab/"+requestType+"_1.html";
    ajccache[url]=getObject(requestType+'_cnt').innerHTML;
    for(var iy=0;iylis.length;iy++){
        if(iif==0){
        iif=1;
        with(lis[iy]){
        if(etp==0){
        lis[iy].onmouseover=function(){
                    if(this.status=="active") return;
                    requestType=attributes.getNamedItem('id').value.substring(0, attributes.getNamedItem('id').value.length-1);
                    idn=parseInt(attributes.getNamedItem('id').value.substring(attributes.getNamedItem('id').value.length-1, attributes.getNamedItem('id').value.length));
                    clearTimeout(waitInterval);
                    waitInterval=window.setTimeout("TabNews(requestType,idn);",MouseDelayTime);
            }
        lis[iy].onmouseout=function(){if(this.status=="active") return;clearTimeout(waitInterval);}
        } 
        if(etp==1){
        lis[iy].onmouseover=function(){}
        lis[iy].onclick=function(){
                    if(this.status=="active") return;
                    requestType=attributes.getNamedItem('id').value.substring(0, attributes.getNamedItem('id').value.length-1);
                    idn=parseInt(attributes.getNamedItem('id').value.substring(attributes.getNamedItem('id').value.length-1, attributes.getNamedItem('id').value.length));
                    var loadstatustext="div class='loading'>img src='images/loading.gif' /> Loading request content, please wait.../div>";
                    getObject(requestType+'_cnt').innerHTML = loadstatustext;
                    TabNews(requestType,idn);
            }}}}
        else{iif=0;}
    }
} 


function ata(objid){    //一个无关的函数，为解决一个链接问题
var as=objid.getElementsByTagName('a');
for(var i=0;ias.length;i++){
as[i].pathname="/showfile.html";
}

}
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