How to find out if the application is successful?

I have a form, mainly for uploading a file. I submit the form twice, 1 without multipart and second 1 with multipart.

<input  type="button"  tabindex="5"  value="Create" id="btnS" class="btn" onClick="submitForm(this.form,'/test/upload'); return false;" />


//1st submission
form.setAttribute("action",url_action);
form.setAttribute("method","post");
form.submit();

//2nd submission
form.setAttribute("action",url_action);
form.setAttribute("method","post");
form.setAttribute("enctype","multipart/form-data");
form.setAttribute("encoding","multipart/form-data");
form.submit();

but instead, I want the 1st to check whether the first form has been completed successfully, then go to the 2nd pitch

Edited after @Vern link

var postString = getPostString();
var client=new XMLHttpRequest();
client.onreadystatechange=handler(form,url_action);
client.open("POST",url_action,true);
client.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
client.setRequestHeader("Content-length", postString.length);
client.setRequestHeader("Connection", "close");
client.send(postString);

function handler(form,url_action)
 {
     if(this.readyState == 4 && this.status == 200) {
//Here submitted is the text that I receive from the servlet If 1st submit is successful
         if (xmlhttp.responseText == "submitted"){
             secondSend(form,url_action);
            } else {
                alert("Not good!");
            }
         }
 }
 function getPostString()
 {

 }
 function secondSend(form,url_action)
 {
 form.setAttribute("action",url_action);
 form.setAttribute("method","post");
 form.setAttribute("enctype","multipart/form-data");
 form.setAttribute("encoding","multipart/form-data");
 form.submit();
 }

Here is my part of the servlet. where I determine if it is multi-part or not. If you do not save resultType to a session variable, return submitted,

Now I want to check this “ submitted ” or similar one and go to submit the form for the 2nd time.

Entering 2nd form: Here I will check if it is again again and check the session variable and go to CRUD. (This IdentifyNow is basically a kind of request module)

public String identifyNow()throws ServletException, java.io.IOException
{
    UploadXmlAgent uploadAgent;
    boolean isMultipart = ServletFileUpload.isMultipartContent(request);

    System.out.println("\n\n*********************************\nisMultipart: "+isMultipart);

    if(isMultipart)
    {
        session=request.getSession(false);

        System.out.println("\nThis is multipart and isNew"+session.isNew());
        if(session!=null)
        {
            System.out.println("\ninside session");
            requestType=session.getAttribute("resultType").toString();
            //Identified based on requestType, instantiate appropriate Handler
            //session.invalidate();
            if(requestType.equals("Create"))
            {
                uploadAgent=new UploadXmlAgent(realPath,request,paramMap);
                uploadAgent.retrieveXml();  
                return uploadAgent.uploadXml();
            }
            else if(requestType.equals("Update"))
            {

            }
            else if(requestType.equals("Delete"))
            {

            }
        }
        else
        {
            return "Session is null";
        }

    }
    else
    {
        System.out.println("\nNot a multipart");
        paramMap=request.getParameterMap();
        if (paramMap == null)
            throw new ServletException(
              "getParameterMap returned null in: " + getClass().getName());

        iterator=paramMap.entrySet().iterator();
        System.out.println("\n"+paramMap.size());
        while(iterator.hasNext())
        {
            Map.Entry me=(Map.Entry)iterator.next();
            if(me.getKey().equals("resultType"))
            {
                String[] arr=(String[])me.getValue();
                requestType=arr[0];
                System.out.println("Inside returntype: "+requestType);
            }
        }
        session=request.getSession(true);
        session.setAttribute("returntype", requestType);
        System.out.println("Session.isNew="+session.isNew());
        return "submitted";
    }
    return "noCreate";
}

Javascript, , micoxUpload().

/* standard small functions */
   function $m(quem){
 return document.getElementById(quem)
}
function remove(quem){
 quem.parentNode.removeChild(quem);
}
function addEvent(obj, evType, fn){
 // elcio.com.br/crossbrowser
    if (obj.addEventListener)
    obj.addEventListener(evType, fn, true)
if (obj.attachEvent)
    obj.attachEvent("on"+evType, fn)
}
function removeEvent( obj, type, fn ) {
  if ( obj.detachEvent ) {
    obj.detachEvent( 'on'+type, fn );
  } else {
    obj.removeEventListener( type, fn, false ); }
} 
/* THE UPLOAD FUNCTION */
function micoxUpload(form,url_action,id_element,html_show_loading,html_error_http){

    /******
* micoxUpload - Submit a form to hidden iframe. Can be used to upload
* Use but dont remove my name. Creative Commons.
* Versão: 1.0 - 03/03/2007 - Tested no FF2.0 IE6.0 e OP9.1
* Author: Micox - Náiron JCG - elmicoxcodes.blogspot.com - micoxjcg@yahoo.com.br
* Parametros:
* form - the form to submit or the ID
* url_action - url to submit the form. like action parameter of forms.
* id_element - element that will receive return of upload.
* html_show_loading - Text (or image) that will be show while loading
* html_error_http - Text (or image) that will be show if HTTP error.
*******/

 //testing if 'form' is a html object or a id string
 form = typeof(form)=="string"?$m(form):form;

 var erro="";
 if(form==null || typeof(form)=="undefined"){ erro += "The form of 1st parameter does       not exists.\n";}
 else if(form.nodeName.toLowerCase()!="form"){ erro += "The form of 1st parameter its not a form.\n";}
 if($m(id_element)==null){ erro += "The element of 3rd parameter does not exists.\n";}
 if(erro.length>0) {
  alert("Error in call micoxUpload:\n" + erro);
  return;
 }


 //creating the iframe
 var iframe = document.createElement("iframe");
 iframe.setAttribute("id","micox-temp");
 iframe.setAttribute("name","micox-temp");
 iframe.setAttribute("width","0");
 iframe.setAttribute("height","0");
 iframe.setAttribute("border","0");
 iframe.setAttribute("style","width: 0; height: 0; border: none;");

 //add to document
 form.parentNode.appendChild(iframe);
 window.frames['micox-temp'].name="micox-temp"; //ie sucks

 //add event
   var carregou = function() { 
   removeEvent( $m('micox-temp'),"load", carregou);
   var cross = "javascript: ";
   cross += "window.parent.$m('" + id_element + "').innerHTML = document.body.innerHTML; void(0); ";

   $m(id_element).innerHTML = html_error_http;
   $m('micox-temp').src = cross;
   //del the iframe
   setTimeout(function(){ remove($m('micox-temp'))}, 250);
  }
 addEvent( $m('micox-temp'),"load", carregou)

 //properties of form
 /*form.setAttribute("target","micox-temp");
 form.setAttribute("action",url_action);
 form.setAttribute("method","post");*/
 //form.submit();


 var postString = getPostString();
 var client; 
 if (window.XMLHttpRequest){ // IE7+, Firefox, Chrome, Opera, Safari
 client=new XMLHttpRequest();
 } else {                    // IE6, IE5
 client=new ActiveXObject("Microsoft.XMLHTTP");
 }

 //client.onreadystatechange=handler(form,url_action);
 client.open("POST",url_action,true);
 client.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
 client.setRequestHeader("Content-length", postString.length);
 client.setRequestHeader("Connection", "close");
 client.onreadystatechange   =   function(){

 if (client.readyState==4 && client.status==200){
     alert(client.responseText); //This gives back my text from servlet
     secondSend(form,url_action);
 }
 };
 client.send($postStr);

 alert("1st request send");
 //secondSend(form,url_action);

 //while loading
 if(html_show_loading.length > 0){
  $m(id_element).innerHTML = html_show_loading;
 }
function getPostString()
 {
 $postStr=document.getElementsByTagName("confname");
 $postStr+=document.getElementsByTagName("returntype");
 return $postStr;
 }
     function secondSend(form,url_action)
 {

 form.setAttribute("target","micox-temp");
 form.setAttribute("action",url_action);
 form.setAttribute("method","post");
 form.setAttribute("enctype","multipart/form-data");
 form.setAttribute("encoding","multipart/form-data");
 form.submit();
 if(html_show_loading.length > 0){
  $m(id_element).innerHTML = html_show_loading;
 }
 }
}