简单的ajax

<!--

var http_request=false;
var meRequest=false;
var ID="";
function createXMLHttpRequest(){
 if(window.XMLHttpRequest) {
  http_request = new XMLHttpRequest();
  meRequest = new XMLHttpRequest();
 }
 else if (window.ActiveXObject) {
  try{
   http_request = new ActiveXObject("Msxml2.XMLHTTP");
   meRequest = new ActiveXObject("Msxml2.XMLHTTP");
  }
  catch(e){
    try{
     http_request = new ActiveXObject("Microsoft.XMLHTTP");
     meRequest = new ActiveXObject("Microsoft.XMLHTTP");
    }catch(e){}
  }
    
 }
  
}
 
function sendmeRequest(url,id) {
 ID=id;
 createXMLHttpRequest();
 meRequest.onreadystatechange = processRequest;
 meRequest.open("GET", url, true);
 meRequest.send(null);
}
// 处理返回信息的函数
function processRequest() {
 if (meRequest.readyState == 4) { // 判断对象状态
  if (meRequest.status == 200) { // 信息已经成功返回，开始处理信息
   var content=document.getElementById(ID);
   content.innerHTML=meRequest.responseText;
   //document.write(content.innerHTML);
  }
        else alert("您所请求的页面有异常。");//页面不正常
 }
}
function show(url,id){
 sendmeRequest(url,id);
 document.getElementById(id).style.display='block';
}
function hide(id){
 var win=document.getElementById(id);
 win.style.display='none';
 
}
-->