julekgwa julekgwa - 11 months ago 47
Javascript Question

FormData does't include the button Javascript

I'm having a problem with

, it was working a couple days ago but now it doesn't work, it submits all the inputs except the submit button. Here's my login form.

<form action="" method="post" name="login_user">
<label for="username">Username/e-mail <span class="error" id="user-error"></span></label>
<input type="text" name="username" id="username" required>
<label for="passwd">Password <span class="error" id="passwd-error"></span></label>
<input type="password" name="passwd" id="passwd" required>
<p><input type="checkbox" checked name="remember"> Remember me <span class="forgot"><a href="<?php echo SITE_URL; ?>/reset">Forgotten password</a></span> </p>
<input type="submit" id="login" value="Login" name="login">
<p>Don't have an account? <a href="<?php echo SITE_URL; ?>/register/">Sign up</a></p>

JS for login, uses MVC.

//ajax login
var login = document.forms.namedItem('login_user');
if (login) {
login.addEventListener('submit', function (e) {
if (validatePassword('passwd', 'passwd-error')) {
var data = new FormData(login);
var userlogin = new XMLHttpRequest();
var btn = document.getElementById('login');
btn.value = 'Login, Please wait...';

userlogin.open('POST', url + 'login/login_user_ajax', true);
userlogin.onload = function (event) {
if (userlogin.status == 200) {
var result = JSON.parse(userlogin.responseText);
if (result.results == 'success.') {
alert('logged in'); //change this later
} else {
document.getElementById('cred-error').innerHTML = result.results;
btn.value = 'Login';
}, false);

The login method in my controller, the button is not detected.

public function login_user_ajax() {

private function login_user($ajax = '')
if (filter_has_var(INPUT_POST, 'login')) {
$new_user = $this->model('User');
$user = trim(filter_input(INPUT_POST, 'username', FILTER_SANITIZE_STRING));
$passwd = trim(filter_input(INPUT_POST, 'passwd', FILTER_SANITIZE_STRING));
if ($new_user->login($user, $passwd)) {
if ($ajax) {
$site_data['results'] = 'success.';
echo json_encode($site_data);
return true;
}else {
$this->redirect(SITE_URL . '/edit');
} else {
if (!$ajax){
return 'The username or password is incorrect.';
}else {
$site_data['results'] = 'The username or password is incorrect.';
echo json_encode($site_data);
return false;
}else {

I get this when I
, with not button.

enter image description here

Answer Source

Because you're not actually using the default submit (instead you're doing ajax), you need to add the clicked button yourself. One easy way to do this is to add a hidden input to your form with the name you want the button to have, and then have all the buttons in the form use this click handler:

function clickHandler() {
    this.form.theHiddenInput.value = this.value;

That way, if a button was used to submit the form, the button's handler sets the value of the hidden input prior to the submit.