var XMLHttpReq;
//XMLHttpRequest       

function createXMLHttpRequest(){
	var ajax=false; 
	try {
		ajax = new ActiveXObject("Msxml2.XMLHTTP");
	} catch (e) { 
		try {
			ajax = new ActiveXObject("Microsoft.XMLHTTP");
		}catch (E){
			ajax = false;
		}
	}
	
	if (!ajax && typeof XMLHttpRequest!='undefined'){
		ajax = new XMLHttpRequest();
	}
	
	return ajax;
}
//
function sendRequest() {
    XMLHttpReq = createXMLHttpRequest();
    var url = "ajax.php";
    XMLHttpReq.open("GET", url, true);
    XMLHttpReq.onreadystatechange = processResponse;//Ö¸Ó¦
   XMLHttpReq.send(null);  // 
  }

// í·µÏ¢
function processResponse() {
		var httptext;
       if (XMLHttpReq.readyState == 4) { // ж϶״̬
              if (XMLHttpReq.status == 200) { // ϢѾɹأʼϢ
                        DisplayHot(XMLHttpReq.responseText);
						//XMLHttpReq.responseText
					setTimeout("sendRequest()", 3000);

              } else { //ҳ治
                    //window.alert("ҳ쳣");
					DisplayHot("page error");
              }
         }
}

// ʾϢĺ
function DisplayHot(str) {
    document.getElementById("txtHint").innerHTML=str;
   }