Send data from doPost() in servlet to AJAX

Question

Hi
I need to send data from my servlet to my html(which contains AJAX), so as per the motivation of the AJAX, this should be done without my webpage reloading / refresh.
my code on the ajax side is something like this:
var xmlHttp = false;
function getXMLHttpRequest(val) {
    try{
         xmlHttp = new XMLHttpRequest();
    }catch(err1){
        try{
             xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
        catch(err2){
            try { xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");}
            catch(err3){ request = null;}
    if (xmlHttp == false) {
        alert("Error creating request object !!");
    else if(xmlHttp != false){
        return xmlHttp;
var xmlhttp = new getXMLObject();
function ajaxFunction() {
       if(xmlHttp) {
        var value1 = document.getElementById("value1");
        xmlHttp.open("POST","ajax_controlller",true); //getname will be the servlet name
        xmlHttp.onreadystatechange  = handleServerResponse;
        xmlHttp.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
        xmlHttp.send("value1=" + value1.value); //Posting txtname to Servlet
function handleServerResponse() {
     if (xmlHttp.readyState == 4) {
          if(xmlHttp.status == 200) {
//            document.myForm.message.innerHTML=xmlHttp.responseText;
            alert(xmlHttp.responseText); //Update the HTML Form element
          else {
             alert("Error during AJAX call. Please try again");
     }and the servlet (doPost()) looks like this :
              if(request.getParameter("value1") != null){
               value = request.getParameter("value1");
          else 
               value = "";
          response.setContentType("text/html");
          response.getWriter().write("helllo");I however, do not understand what is wrong, do I need to specify the name of the html file just like we do in case of RequestDispatcher() methods. I dont think that is the case here ?

Answer 1

The problem is: My value is passed correctly from my HTML(ajax) file to the servlet but I am not able to send the result(or data) from the servlet to the HTML (ajax) file, I know I can do this easily by session management but I need to establish this without the session management , In the servlet I use
response.setContentType("text/html");          
response.getWriter().write("helllo");
and in the HTML file I use
function handleServerResponse() {
     if (xmlHttp.readyState == 4) {
          if(xmlHttp.status == 200) {
            alert(xmlHttp.responseText); //Update the HTML Form element
          else {
             alert("Error during AJAX call. Please try again");
        }so as per the logic I should get the alert as the result sent by the servlet on the same html page, but instead the servlet writes the hello on the new page, the URL of this page is the address of the servlet itself, so I conclude that I am not able to establish the connection between the servlet and the html file. Could you clarify this please ?