Ajax标签导航效果(仿网易首页)

代码如下：

<!-- 
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;iy<lis.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;i<as.length;i++){ 
as[i].pathname="/showfile.html"; 
} 

} 
//-->