前端：//取消关注 functionfunction qxGzFun(userId,followId){    if(window.XMLHttpRequest){         xmlObj = new XMLHttpRequest();    }else if(window.ActiveXObject){         xmlObj = new ActiveXObject("Microsoft.XMLHTTP");    }else {       return;    }    xmlObj.onreadystatechange = handleResponse;        //我们通过这个对象的OPEN方法向服务发送请求，该函数声明为XMLHttpRequest.open(String method, String URL, boolean asynchronous);    //method是请求的方式，可以为GET和POST URL是你要请求的资源 asynchronous是布尔类型，为true表示交互设置为异步     xmlObj.open("post","${basePath}index.do?method=toMyzoneFsQxgz",true);        //xmlObj.send("");调用send()（参数是空或是null）将会发起一次请求，对于GET方式的请求，两次同样的请求将会得到相同的结果，由于为将交互设置为异步方式，    //因此要为指定一个回调函数：xmlObj.onreadystatechange = callBackFunction;剩下的事就交给回调函数处理了。有一点要注意了，用Servlet或JSP来响应异步请求时，    //要设置reponse的contentType属性指明是XML格式：response.setContentType("text/xml");        xmlObj.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");    xmlObj.send("followId="+followId+"&userId="+userId);       //window.location.href="${basePath}index.do?method=toMyzoneFsQxgz&param=1&userId="+fdUserId+"&followId="+followId+"&currentPage=${pageDataOne.currentPage}";}function handleResponse(){    if (xmlObj.readyState == 4){//xmlObj loaded        if (xmlObj.status == 200){               alert(xmlObj.responseText+"!");               window.location.href="${basePath}index.do?method=toMyzoneFs&currentPage=${pageData.currentPage}";                         // confirm(xmlObj.responseText+"!");                         // prompt(xmlObj.responseText+"!");                         //window.location.reload();               //var followNumDiv = document.getElementById('followNumDiv');               //  followNumDiv.innerHTML = "${followNum}";        }   }}后台：public ActionForward toMyzoneFsQxgz(ActionMapping mapping, ActionForm form,   HttpServletRequest request, HttpServletResponse response){    String userId = request.getParameter("userId");    String followId = request.getParameter("followId");    //取消关注     String msg = userFollowService.cancelUserRelation(userId, followId);      try {            response.setHeader("Cache-Control", "no-cache");            response.setContentType("text/xml;charset=utf-8");            PrintWriter pw = response.getWriter();            pw.print(msg);            pw.close();      } catch (IOException e) {         e.printStackTrace();      }      return null;}