javascript請求servlet實現ajax示例(分享)

function sendRequestByGet(){
 //定義異步請求對象
 var xmlReq;
 //檢測瀏覽器是否直接支持ajax
 if(window.XMLHttpRequest){//直接支持ajax
 xmlReq=new XMLHttpRequest();
 }else{//不直接支持ajax
 xmlReq=new ActiveObject('Microsoft.XMLHTTP');
 }
 
 //設置回調函數
 xmlReq.onreadystatechange=function(){
 if (xmlReq.readyState==4&&xmlReq.status==200) {
  //獲取服務器的響應值
 var result=xmlReq.responseText;
  //后續操作
  alert(result);
 }
 };
 
 //創建異步get請求
 var url="Hello?name=zhangsan";
 xmlReq.open("GET",url,true);
 //發送請求
 xmlReq.send(null);
 }

function sendRequestByPost(){
 //定義異步請求對象
 var xmlReq;
 //檢測瀏覽器是否直接支持ajax
 if(window.XMLHttpRequest){//直接支持ajax
 xmlReq=new XMLHttpRequest();
 }else{//不直接支持ajax
 xmlReq=new ActiveObject('Microsoft.XMLHTTP');
 }
 
 //設置回調函數
 xmlReq.onreadystatechange=function(){
 if (xmlReq.readyState==4&&xmlReq.status==200) {
  //獲取服務器的響應值
 var result=xmlReq.responseText;
  //后續操作
  alert(result);
 }
 };
 
 //創建異步Post請求
 var url="Hello";
 xmlReq.open("POST",url,true);
 xmlReq.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
 //發送請求
 var data="name=lisi";
 xmlReq.send(data);
 }

@Override
 protected void doPost(HttpServletRequest req, HttpServletResponse resp)
 throws ServletException, IOException {
 String name=req.getParameter("name");
 PrintWriter out = resp.getWriter();
 out.print(name);
 }