How do I send "unlimited" text in a parameter using "POST" in Ajax

Question

I'm trying to send large amounts of text data to the server using POST rather than GET, using Ajax
However, I am only able to send a max of 9.76 kb
I start with a jsp page, which calls a javascript method that utilises Ajax, which sends the text in a parameter in a XMLHttpRequest object
to a servlet. The text is derived from options values in a multi select combo box.
Here's my code:
Code snippet from .jsp page:
        <table>
        <form name="form1" id="form1" method="POST">
           <tr>
              <td>
             <select name="sel" id="sel" multiple="multiple" size="0"></select>
          </td>
          <td>
             <input type="button" id="sendOpts" name="sendOpts" value="Send Options" onClick="jsObj.sendOpts()">
          </td>
          </tr>
       </form>
       </table>Code snippet from jsObj.js file:
//=================================================
// jsObj object
//=================================================
jsObj = new jsObj();
function jsObj() {
     this.sendOpts = function() {
          if(!confirm('Send Option Values?'))
               return;
          if (window.XMLHttpRequest) { // code for IE7+, Firefox, Chrome, Opera, Safari
               xmlhttp=new XMLHttpRequest();
          } else { // code for IE6, IE5
               xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
          xmlhttp.onreadystatechange=function() {
               if(xmlhttp.readyState==4) { // 4 = The request is complete
                    if (xmlhttp.status==200 || window.location.href.indexOf("http")==-1) {
                         alert(xmlhttp.responseText); // When I copy and paste all the text from this alert to text editor and save the file, the largest the file can be is 9.76 kb.
          var url = 'testSize'; // Servlet that simply retrieves the sent String in a parameter and sends it back to this method
          var sel = document.getElementById('sel');
          var str = sel.name + '=';
          var delim = ':';
          for(var i = 0; i < sel.length; i++) {
               str += encodeURIComponent(sel.options.value + delim); // 'encodeURIComponent' encodes any special characters within the parameter values
          xmlhttp.open("POST",url,true);
          xmlhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded"); // This is needed for any POST request made via Ajax
          xmlhttp.send(str); // send the parameter and it's value to the servlet
}Code snippet from 'testSize' servlet:package test;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.*;
public class TestSize extends HttpServlet {
     public synchronized void doGet(HttpServletRequest request,
          HttpServletResponse response) throws ServletException,IOException {
          PrintWriter out = null;
          try {
               response.setContentType("text/html");
          out = response.getWriter();
               String str = request.getParameter("sel");
               str = str.substring(0, str.length()-1); // cut off last delimiter
               out.println(str);
               } catch (Exception e) {
     public synchronized void doPost(HttpServletRequest request,
          HttpServletResponse response) throws ServletException, IOException {
          doGet(request, response);
}Any help greatly appreciated.
Edited by: Irish_Fred on Feb 25, 2010 5:14 AM                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               

Answer 1

Yes, I tried that.
I set the "ACTION" of the form to the servlet and then used the form.submit() method to POST the text to the servlet.
i.e.: I selected many options in the select combo, concatenated them to one string, set the 'value' property of a form text field to
this string, did a 'form.submit()' to the servlet and I was able to send a much larger amount of text.
( The .txt file I saved from the resulting text equaled about 30 kb in size, so obviously I can send much more
data this way. )
However, I want to use Ajax, so I don't have to reload the page. I 'borrowed' the Ajax part of the code from a website:
http://www.javascriptkit.com/dhtmltutors/ajaxgetpost2.shtml
and I presumed that because the author used "POST" as opposed to "GET", I would be able to send larger
chunks of data. Obviously not, or there's another reason for the limit of data I can send using my present code,
which I'm not seeing. I'm fairly new to jsp, Ajax & Servlets, so this is no surprise.
If anyone can point out to me where I'm going wrong, I'd greatly appreciate it. Cheers.