How to Replace Form Without Triggering the Change Event? - javascript

I would like to validate a form with an AJAX request to the server and then swap the form html in the web browser with the form html from the server because this would be an easy implementation in theory. It is proving a nightmare though because the change event is triggered without the user interacting further after the first interaction which triggered the first change event. Consequently an infinite loop of AJAX requests to the server is happening.
The html form sits inside a div which has classes 'container mb-4'. This is the JS code -
var _cont = $('.container.mb-4')
var _form = $('.custom-form')
function ajax_validation(form) {
form.on('change', 'input, select, textarea', function() {
form_data = form.serialize()
$.ajax({
url: "/form/6/",
type: "POST",
data: form_data,
success: function(data) {
if(!(data['success'])) {
_cont.empty()
_cont.append(data['form_html'])
form = _cont.find('form')
ajax_validation(form)
}
},
error: function () {
form.find('.error-message').show()
}
});
})
}
ajax_validation(_form)
The change event I am assuming is triggered because the server returns a form input field with a different csrf token as the value to the previous input field - all other fields are the same. So an obvious solution would be to keep the same csrf token. But I want to understand why the JS code isn't working. I thought destroying the form would destroy the change event bound to it. So am at a loss to explain this infinite loop. How do I change this so I can just swap the form and not trigger another change event until the user really does change something?

It's not a good thing to use events in function no need to do that
Also your event here for input , select , textarea for serialize you need to select the closest() form
Try the next code
var _cont = $('.container.mb-4');
var _form = $('.custom-form');
_cont.on('change', 'form input,form select,form textarea', function() {
var ThisForm = $(this).closest('form');
var form_data = ThisForm.serialize();
$.ajax({
url: "/form/6/",
type: "POST",
data: form_data,
success: function(data) {
if(!(data['success'])) {
_cont.html(data['form_html']);
}
},
error: function () {
ThisForm.find('.error-message').show()
}
});
});
And logically if(!(data['success'])) { should be if(data['success']) {

First let's understand the issue that you have. You have a function called ajax_validation that is defining a change event on the form's elements which, on response will call ajax_validation. So, if any change happens on your elements, then a new request is sent to the server. So, if any value is changed, like a token, the request will be sent again. You could use a semaphore, like this:
var semaphore = true;
function ajax_validation(form) {
form.on('change', 'input, select, textarea', function() {
if (!semaphore) return;
semaphore = false;
form_data = form.serialize()
$.ajax({
url: "/form/6/",
type: "POST",
data: form_data,
success: function(data) {
if(!(data['success'])) {
_cont.empty()
_cont.append(data['form_html'])
form = _cont.find('form')
ajax_validation(form)
}
semaphore = true;
},
error: function () {
form.find('.error-message').show()
}
});
})
}
Something like this should solve your issue for the time being, but you should consider refactoring your code, because what you experience is well-known and is called callback hell.

Turns out the password field was coming back blank from the server - this django must do out of the box if the PasswordInput widget is used. So the form is replaced with a new form which lacks the password input from the before. The browser was then applying the autofill password value to the form which was triggering the change event.
This is my code now. It checks that the form_data about to be sent for validation really is different to before minus the csrf token which will be different.
It is based on Mohamed's answer -
var _cont = $('.container.mb-4');
var _form = $('.custom-form');
var prev_data = undefined
_cont.on('change', 'form input,form select,form textarea', function() {
var ThisForm = $(this).closest('form');
var form_data_wo_csrf = ThisForm.find("input, textarea, select").not("input[type='hidden']").serialize()
if(form_data_wo_csrf == prev_data) {
return
}
var form_data = ThisForm.serialize()
$.ajax({
url: "/form/6/",
type: "POST",
data: form_data,
success: function(data) {
if(!(data['success'])) {
_cont.html(data['form_html']);
prev_data = form_data_wo_csrf
}
},
error: function () {
ThisForm.find('.error-message').show()
}
});
});

Related

POST output into a modal from any form class on page

Sorry I am a beginner with jQuery and Javascript. I want to be able to get the results into my modal from any form on the page that has class ajax. My code is below but not working correctly. Currently it opens the post result in a new page and not in the modal. Can anyone shed any light on my code?
Many thanks
$(document).ready(function() {
$('.ajax').click(function() {
var that = $(this),
url = that.attr('action'),
type = that.attr('method'),
data = {};
that.find('name').each(function(index, value) {
var that = $(this),
name = that.attr('name'),
value = that.val();
data[name] = value;
});
console.log(value);
// AJAX request
$.ajax({
url: url,
type: type,
data: data,
success: function(response){
// Add response in Modal body
$('.modal-body').html(response);
// Display Modal
$('#aaModal').modal('show');
}
});
});
});
This probably happens because your browser submits the form by default. It doesnt know youre doing AJAX stuff. To prevent this, use preventDefault().
In addition to that, jQuery has a built in function for serializing (1 and 2) form data.
$(document).ready(function() {
$('form.ajax').click(function(event) {
event.preventDefault(); // prevents opening the form action url
var $form = $(this),
url = $form.attr('action'),
type = $form.attr('method'),
data = $form.serialize();
// console.log(value); // value doesnt exist outside of your loop btw
// AJAX request
$.ajax({
url: url,
type: type,
data: data,
success: function(response){
// Add response in Modal body
$('.modal-body').html(response);
// Display Modal
$('#aaModal').modal('show');
}
});
});
});
Also, its not quite clear if you bind the click event handler to a form or a button, I guess the first one. You should change the handler to the following:
$(document).ready(function() {
$('form.ajax').on('submit', function(event) {

Stop an ajax request from posting data until a response is received?

i have written a basic commenting system which is a simple write to database form and it uses ajax as well.
The issue is that if i enter my message, and then spam send / the enter key it seems to stack up and then everything is written to the database multiple times.
My ajax is like so:
$(document).ready(function(){
$(document).on('submit', '.addcomment', function() {
var $targetForm = $(this);
$.ajax({
type: "POST",
url: "process/addcomment.php",
data: $targetForm.serialize(),
dataType: "json",
success: function(response){
if (response.databaseSuccess == true) {
$("#container").load("#container");
$targetForm.find('#addcommentbutton').attr("disabled", true);
}
else {
$ckEditor.after('<div class="error">Something went wrong!</div>');
}
}
});
return false;
});
});
The submit button does become disabled, but the form can still be entered via the enter keyboard button or even still with a mass spam of the submit button (which is supposed to be disabled)
Is there a way to 100% disable this form with jquery, until the success JSON message is received?
Anymore code just let me know!
In this case, i would not use delegation. I would instead bind the event directly to the form using .one since each form should submit only once (if that's the case.) If you instead only have one addComment form, then i question why you are using delegation in the first place.
$(commentForm).appendTo(selector).one("submit",function(e){
e.preventDefault(); // prevent this submit
$(this).submit(false); // prevent future submits
// submit data to server
})
Just keep track of if a request is in progress:
$(document).ready(function(){
var isSubmitting = false;
$(document).on('submit', '.addcomment', function() {
var $targetForm = $(this);
if (!isSubmitting) {
isSubmitting = true;
$.ajax({
...
success: function(response){
...
},
complete: function() { isSubmitting = false; }
});
}
});
There are lots of ways to handle this, but the best involves validating the data on the server end. You want to prevent people from overloading the database inadvertently (the "fat finger" problem) or deliberately (the bored script kiddie who decides to crash your server or fill your database with garbage).
The best solution:
Generate a one-time token when the page is requested (called a "nonce")
Post that nonce when you post the data
Only accept it on the server side if the nonce has never been used
This obviously requires you to keep track of a list of valid nonces, but it prevents any glitches or abuse of the send button.
Also, as others have pointed out, disable the button much earlier and only run the submit action handler once. That will help with the inadvertent double-clicks and so on, but you also need the nonce to prevent compulsive clickers or intentional misuse.
Can you do it like below:
$(document).ready(function(){
var isAjaxInProgress = null;
$(document).on('submit', '.addcomment', function() {
var $targetForm = $(this);
if(isAjaxInProgress === null || !$isAjaxInProgress ){
isAjaxInProgress = true;
$.ajax({
type: "POST",
url: "process/addcomment.php",
data: $targetForm.serialize(),
dataType: "json",
success: function(response){
if (response.databaseSuccess == true) {
$("#container").load("#container");
$targetForm.find('#addcommentbutton').attr("disabled", true);
}
else {
$ckEditor.after('<div class="error">Something went wrong!</div>');
}
isAjaxInProgress = false;
}
});
}
return false;
});
});
// declare a global ajax request variable
var is_request_sent = false;
function send_msg()
{
if(is_request_sent == false)
{
$.ajax({
type: "POST",
url: "process/addcomment.php",
data: $targetForm.serialize(),
dataType: "json",
success: function(result){
//alert(result);
is_request_sent = false;
},
error: function(a,b,c)
{
is_request_sent = false;
},
beforeSend: function(jqXHR, plain_jqXHR){
// set request object
is_request_sent = jqXHR;
// Handle the beforeSend event
},
complete: function(){
// update global request variable
is_request_sent = false;
// Handle the complete event
}
});
}
}

How to refresh submitHandler in jQuery Validation

I'v got a problem with jQuery Validation plugin.
When I defined custom submitHandler, it's stored after first validation run.
I'm using submitHandler to send the Object via AJAX request, but when the object is changed after event trigger, it wont change in submit handler function.
Is there any way to refresh submit handler after each event trigger?
My code
$('.request-telephone-form-submit').click(function(){
var thisForm = $(this).closest('form');
var postVars = new Object();
postVars.name = $('.request-name').val();
postVars.phone = $('.request-phone').val();
thisForm.closest('form').validate({
rules:
{
Name: {
required: true,
},
Telephone: {
required: true,
}
},
submitHandler: function(){
$.ajax({
type: 'POST',
url: '...',
data : postVars,
success : function(response) {
}
});
}
})
});
You've got a couple errors here.
Move your $.validate call out of the click handler, and just do it directly in a $(document).ready block:
$(document).ready(function(){
$('#formID').validate({
//options here
});
});
If your $('.request-telephone-form-submit') is a submit button in the form, it will automatically validate when the button is clicked. If the form validates according to your rules, then it will call the submitHandler function. At that time you can collect your post variables like so:
submitHandler: function(form){
var postVars = new Object();
postVars.name = $('.request-name').val();
postVars.phone = $('.request-phone').val();
$.ajax({
type: 'POST',
url: '...',
data : postVars,
success : function(response) {
}
});
}
Try to handle event on your form tag and use $('form.formClass').on('submit', function(){}) that is better jQuery way

AJAX success callback only carrying out first function

I've got a simple form submission that upon success I've got an alert and a call to clear the form. I do get the alert, the info gets successfully added to the database, but the second call--for the form to clear, is not being carried out. I'm sure it's something simple I'm doing wrong, but I can't figure it out.
$('#contact_submit').click(function(e){
if ($("#submit_form_contact").valid()) {
var post_data = {
"name" : $('#name').val(),
"email" : $('#email').val(),
"inquiry" : $('#inquiry_dropdown option:selected').text(),
"message" : $('#message').val()
};
$.ajax({
type: "POST",
url: "process-contact.php",
data: post_data,
success: function(data) {
alert("Thank you for contacting us.");
$('#submit_form_contact').reset();
}
});
e.preventDefault();
}
Also, the submit button is just a button, not a submit input. Is it necessary to preventDefault()? I'm new at this.
jQuery doesn't have a .reset() method.
Do this instead:
$('#submit_form_contact')[0].reset();
This grabs the first DOM element, and invokes the native .reset(). If there's any chance the form won't be found, then test for the element.
var f = $('#submit_form_contact')[0];
if (f)
f.reset();
And of course you don't really need jQuery to get an element by ID, especially if you're not going to use any jQuery methods.
var f = document.getElementbyId('submit_form_contact');
if (f)
f.reset();
Another alternative would be to set the submit button as the context: of the ajax call, then use its form property.
$.ajax({
context: this,
type: "POST",
url: "process-contact.php",
data: post_data,
success: function(data) {
alert("Thank you for contacting us.");
this.form.reset();
}
});
this line can be used too
$("#submit_form_contact").trigger('reset');

jQuery override event.preventDefault()

I have a form that, when submitted, goes through the usual e.preventDefault() and sends an ajax request instead. However, if this ajax request returns a certain condition, I want the form to be submitted normally. How do I achieve this?
// Submit handler
$(".reserveer_form").submit(function(event){
event.preventDefault();
$.ajax({
url: $(this).attr("action"),
data: $(this).serialize(),
success: function(data) {
if($(".messagered",data).length > 0){
var errors = $(".messagered",data);
$(".gegevens").before(errors);
} else {
// SUBMIT THE FORM!
}
}
});
})
Invoke the native submit method on the form, so that it doesn't trigger the jQuery handler.
$.ajax({
context: this, // <-- set the context.
url: $(this).attr("action"),
data: $(this).serialize(),
success: function (data) {
if ($(".messagered", data).length > 0) {
var errors = $(".messagered", data);
$(".gegevens").before(errors);
} else {
this.submit(); // <-- submit the form
}
}
});
Since your comment says you change a form variable, you could start your submit handler by checking that same form variable. If it is changed, just return true. If not, continue with the current handler.
You can use the submit() method or forms:
$(".reserveer_form").submit(function(event){
event.preventDefault();
var form = this,
$form = $(form);
$.ajax({
url: $form.attr("action"),
data: $form.serialize(),
success: function(data) {
var errors = $(".messagered", data);
if (errors.length > 0){
$(".gegevens").before(errors);
} else {
form.submit();
}
}
});
})
However, this seems to be a strange ajax request. First, you send the form (serialized, via ajax) to the server, and when the response contains no errors you send it again? The server would process it twice (and act twice, depending on your form). Also, the user does not get a message that his input is already processed - he clicks "submit", and it always takes a time until it is visibly submitted (where he even could change some input).

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