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How to submit form without reloading page, without jQuery?

I have form as follows, it require to sent an action to my java Servlet to do an update to the database.
How do I submit the form without the page get reloaded here?
Currently with action="myServlet" it keep direct me to a new page. And if I remove the action to myServlet, the input is not added to my database.
<form name="detailsForm" method="post" action="myServlet"
onsubmit="return submitFormAjax()">
name: <input type="text" name="name" id="name"/> <br/>
<input type="submit" name="add" value="Add" />
</form>
In the view of my Java servlet, request.getParameter will look for the name and proceed to add it into my db.
#Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
if (request.getParameter("add") != null) {
try {
Table.insert(name);
} catch (Exception ex) {
ex.printStackTrace();
}
}
}
In my JavaScript part, I have a submitFormAjax function
function submitFormAjax()
{
var xmlhttp;
if (window.XMLHttpRequest) {
// code for modern browsers
xmlhttp = new XMLHttpRequest();
} else {
// code for IE6, IE5
xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange = function() {
if (xmlhttp.readyState == 4 && xmlhttp.status == 200)
alert(xmlhttp.responseText); // Here is the response
}
var id = document.getElementById("name").innerHTML;
xmlhttp.open("POST","/myServlet",true);
xmlhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xmlhttp.send("name=" + name);
}

A similar question was asked here
Submit form without reloading page
Basically, do "return false" after invoking the function. Something like this should work:
<form name="detailsForm"
method="post"
action="myServlet"
onsubmit="submitFormAjax();
return false;"
>

This is how I used to implement Ajax in JS without JQuery. As am a PHP and JS guy I cant possibly help you with Java Servlet side but yes heres my little help from JS side. This given example is a working example.See if it helps you.
// HTML side
<form name="detailsForm" method="post" onsubmit="OnSubmit(e)">
// THE JS
function _(x){
return document.getElementById(x);
}
function ajaxObj( meth, url )
{
var x = false;
if(window.XMLHttpRequest)
x = new XMLHttpRequest();
else if (window.ActiveXObject)
x = new ActiveXObject("Microsoft.XMLHTTP");
x.open( meth, url, true );
x.setRequestHeader("Content-type", "application/json");
return x;
}
function ajaxReturn(x){
if(x.readyState == 4 && x.status == 200){
return true;
}
}
function OnSubmit(e) // call this function on submit
{
e.preventDefault();
var username = _("name").value;
if (username == "")
{
alert("Fill out the form first");
}
else
{
var all = {"username":username};
all = JSON.stringify(all);
var url = "Myservlet";
var ajax = ajaxObj("POST", url);
ajax.onreadystatechange = function()
{
if(ajaxReturn(ajax) == true)
{
// The output text sent from your Java side in response
alert( ajax.responseText );
}
}
//ajax.send("user="+username+");
ajax.send(all);
}
}
Thanks

Change the code in form
onsubmit="submitFormAjax(event)"
Change your JS code
function submitFormAjax(e)
{
e.preventDefault();
var xmlhttp;
if (window.XMLHttpRequest) {
// code for modern browsers
xmlhttp = new XMLHttpRequest();
}
......
................
...............
return false; //at last line

Using JavaScript code for navigating (InnerHTML)

I'm using this code below for the navigation system on my site, the purpose is to open an HTML page within a div .. (InnerHTML), but, when I'm clicking one of my menu links I'm getting the JavaScript notification "Problem: " (see "else" in the JavaScript code block). This code is fixed (good) for SEO aspect.
Can someone please tell me what the problem with it is? I'm trying to preserve the code as it is as much as possible.
Thank you in advance for your help!
JavaScript code:
function processAjax(url)
{
if (window.XMLHttpRequest) { // Non-IE browsers
req = new XMLHttpRequest();
req.onreadystatechange = targetDiv;
try {
req.open("GET", url, true);
}
catch (e) {
alert(e);
}
req.send(null);
} else if (window.ActiveXObject) { // IE
req = new ActiveXObject("Microsoft.XMLHTTP");
if (req) {
req.onreadystatechange = targetDiv;
req.open("GET", url, true);
req.send();
}
}
return false;
}
function targetDiv() {
if (req.readyState == 4) { // Complete
if (req.status == 200) { // OK response
document.getElementById("containerDiv").innerHTML = req.responseText;
} else {
alert("Problem: " + req.statusText);
}
}
}
In HTML body:
<a onclick="return processAjax(this.href)" href="example.html">CLICK ME</a>
<div id="containerDiv"></div>

The server returned a non-200 response. If you're using a debugger like Firebug, Chrome Developer, or IE Developer, check the Network tab to see exactly where your XHR went, and what the response was.

xmlHttpRequest.send(Params) not working in tomcat 7

I am trying to send some parameters through xmlHttpRequest.send(params) written in a JS file to my servlet where I try to get the parameters by req.getParameter("some_Parameter"); it returns null on the servlet. though if i send the parameters by appending them in url it works fine. but when the url will be large it will break the code. so please someone help me out.
Thanks in advance.
function doHttpPost(theFormName, completeActivity)
{
var xmlhttp = new ActiveXObject("MSXML2.XMLHTTP");
var xmlMessage = buildPOST(theFormName, completeActivity);
var responseTxt;
try {
xmlhttp.Open(document.forms[theFormName].method, document.forms[theFormName].action+'?'+xmlMessage, false);
xmlhttp.onreadystatechange=function() {
if (xmlhttp.readyState==4) {
responseTxt = xmlhttp.responseText;
}
}
xmlhttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
enableDisableLinks(true);
setPointer();
xmlhttp.Send();
if(xmlhttp.Status != 200) {
alert("Post to server failed");
}
} catch (e) {
responseTxt = "Exception while posting form data: Error No: " + e.number + ", Message: " + e.description;
}
resetPointer();
enableDisableLinks(false);
var expectedTxt = "Form Data had been successfully posted to the database."
if(responseTxt.toString() == expectedTxt.toString()) {
// MNP: New requirement from Jeanne, should not refresh CM page, commenting it off for now
//if(completeActivity) {
// if (typeof (ViewCaseDetailBtn) != 'undefined') {
// ViewCaseDetailBtn.click();
// }
//}
return true;
} else {
alert (responseTxt);
}
return false;
}

BUGS
//IE only - shooting yourself in the
// Not all IE versions use ActiveX!
var xmlhttp = new ActiveXObject("MSXML2.XMLHTTP"); foot.
//JavaScript case sensitive, open !== Open
xmlhttp.Open(document.fo...
//JavaScript case sensitive, send !== Send
xmlhttp.Send();
//JavaScript case sensitive, status !== Status
xmlhttp.Status
AND if you are using synchronous, it does not call the onreadystatechange.
If you are using POST, the value needs to be in send("valuestosendup") not on the querystring.
This code shows why you should really use a framework to make Ajax calls and to not roll your own.

Getting the responseText from XMLHttpRequest-Object

I wrote a cgi-script with c++ to return the query-string back to the requesting ajax object.
I also write the query-string in a file in order to see if the cgi script works correctly.
But when I ask in the html document for the response Text to be shown in a messagebox i get a blank message.
here is my code:
js:
<script type = "text/javascript">
var XMLHttp;
if(navigator.appName == "Microsoft Internet Explorer") {
XMLHttp = new ActiveXObject("Microsoft.XMLHTTP");
} else {
XMLHttp = new XMLHttpRequest();
}
function getresponse () {
XMLHttp.open
("GET", "http://localhost/cgi-bin/AJAXTest?" + "fname=" +
document.getElementById('fname').value + "&sname=" +
document.getElementById('sname').value,true);
XMLHttp.send(null);
}
XMLHttp.onreadystatechange=function(){
if(XMLHttp.readyState == 4)
{
document.getElementById('response_area').innerHTML += XMLHttp.readyState;
var x= XMLHttp.responseText
alert(x)
}
}
</script>
First Names(s)<input onkeydown = "javascript: getresponse ()"
id="fname" name="name"> <br>
Surname<input onkeydown = "javascript: getresponse();" id="sname">
<div id = "response_area">
</div>
C++:
int main() {
QFile log("log.txt");
if(!log.open(QIODevice::WriteOnly | QIODevice::Text))
{
return 1;
}
QTextStream outLog(&log);
QString QUERY_STRING= getenv("QUERY_STRING");
//if(QUERY_STRING!=NULL)
//{
cout<<"Content-type: text/plain\n\n"
<<"The Query String is: "
<< QUERY_STRING.toStdString()<< "\n";
outLog<<"Content-type: text/plain\n\n"
<<"The Query String is: "
<<QUERY_STRING<<endl;
//}
return 0;
}
I'm happy about every advice what to do!
EDIT: the output to my logfile works just fine:
Content-type: text/plain
The Query String is: fname=hello&sname=world
I just noticed that if i open it with IE8 i get the query-string. But only on the first "keydown" after that IE does nothing.

You don't have to use javascript: in on___ handler, just onkeydown="getresponse();" is enough;
IE>=7 supports XMLHttpRequest object, so directly checking if XMLHttpRequest exists is better than checking whether navigator is IE. Example:
if(XMLHttpRequest) XMLHttp=new XMLHttpRequest();
else if(window.ActiveXObject) XMLHttp=new ActiveXObject("Microsoft.XMLHTTP");
inside your getresponse() function, try to add below code at the beginning (before open):
try{XMLHTTP.abort();}catch(e){}
Because you're using a global object, you may want to "close" it before opening another connection.
Edit:
Some browser (maybe Firefox itself?) do not handle non-"text/xml" response very well in default state, so to ensure things and stuffs, try this:
function getresponse () {
try{XMLHttp.abort();}catch(e){}
XMLHttp.open("GET", "http://localhost/cgi-bin/AJAXTest?" + "fname=" +
document.getElementById('fname').value + "&sname=" +
document.getElementById('sname').value,true);
if(XMLHttp.overrideMimeType) XMLHttp.overrideMimeType("text/plain");
XMLHttp.send(null);
}

My problem had nothing to do with the code...
I was testing my script on the local IIS7 and I opened the html-page with double-clicking on the file. But you have to open the webpage via browser (localhost/mypage.htm) because otherwise for the browser the html and the executable have different origins. which is not allowed.

xmlhttprequest: "password" from txt-file

I'm new to javascript/ajax and a bit stuck right now.
The assignment is to use only javascript/ajax.
I'm supposed to make a login-form, and when typing in the right password it will display a "secret message". Currently this message is an alert-box.
This is in the script for validating the form input:
var riktigPassord = 'password';
var passord = window.document.passordSkjema.passord.value;
if (passord == riktigPassord ) {
alert("Dette er en hemmelig beskjed");
window.document.passordSkjema.passord.focus();
return true;
}
else {
alert("Innlogging mislyktes. Passord er feil!");
window.document.passordSkjema.passord.focus();
return false;
}
}//slutt på funksjonen her
And this is the code for the form:
<form name="passordSkjema" action="#" method="post"
onSubmit="return validerPassord();">
Passord: <input type="text" name="passord"><br>
<input type="submit" name="knapp">
</form>
I'm supposed to get the password from a txt-file. (still using only javascript)
and in my case, the txt-filename is "password.txt".
I've never done this before, but I think I know how to make a XHR-object... xD
// New XMLHttpRequest-object
function newXHRobjekt() {
try {
XHRobjekt = new XMLHttpRequest(); // Firefox, Opera, ...
} catch(err1) {
try {
XHRobjekt = new ActiveXObject("Microsoft.XMLHTTP"); // Noen IE
} catch(err2) {
try {
XHRobjekt = new ActiveXObject("Msxml2.XMLHTTP"); // Noen IE
} catch(err3) {
XHRobjekt = false;
}
}
}
return XHRobjekt;
}
So.. My question is. How do I use a XHR-object to get use the functions above to check the password-input against password.txt. the file only contains the password (for instance only "12345"). and also I would like to know how to get the "secret message" from another txt-file.
I'm aware that this isn't secure at all, but it's a part of understanding javascript/Ajax, in my classes.
Thanks!

add the following code to the onload event of the body.
var passwordLoaded = false;
var password = "";
var secretMessageLoaded = false;
var secretMessage = "";
var xhr = newXHRobjekt();
xhr.open("GET", "password.txt");
xhr.onreadystatechange = function() {
if (xhr.readyState == 4) {
password = xhr.responseText;
passwordLoaded = true;
}
}
xhr.send(null);
xhr = newXHRobjekt();
xhr.open("GET", "secret_message.txt");
xhr.onreadystatechange = function() {
if (xhr.readyState == 4) {
secretMessage = xhr.responseText;
secretMessageLoaded = true;
}
}
xhr.send(null);
If both passwordLoaded and secretMessageLoaded are set to true you can use the variables password and secretMessage.

Like many of the Javascript APIs XHR object too have an async interface. So you will need to define callback functions to handle the responses:
xmlhttp.open("POST", "http://example.com",true);
xmlhttp.onreadystatechange=function() {
if (xmlhttp.readyState==4) {
alert(xmlhttp.responseText)
}
}
xmlhttp.send('my request data');
Search for example on the net. I found a post, a bit old but seem to have good examples.