Develop Reference

Ajax form is sent twice if validation errors take place

I know about event.preventDefault() and event.stopImmediatePropagation(). But it doesn't work for me. In my case I have such ajax call:
$('#templateConfirmDialog').on('show.bs.modal', function (event) {
$(this).find('.modal-yes').click(function(){
var form = form2js('search_form', '.', true, function (node) {}, false);
var requestData = JSON.stringify(form, replacer);
var $formErrors = $('.search_form').find('.alert-danger');
event.preventDefault();
event.stopImmediatePropagation();
$.ajax({
type: 'POST',
contentType : "application/json",
url: '/fraud/template/testCreate',
data: requestData,
dataType: 'json',
success: function (data) {
$formErrors.text('');
//if no errors just reload
if (data === undefined || data.length === 0) {
location.reload();
}
else {
//else bind error messages
data.forEach(function(error) {
$('#new-' + error.field + '-error').text(error.defaultMessage);
})
}
}
});
});
My problem is that the ajax call is prevented as much times as I made attempts to input data. If I entered invalid data once - ajax is called twice. If twice - 3 times. What may be a reason of such behavior?

Every time this event happens:
$('#templateConfirmDialog').on('show.bs.modal', function (event) {
You bind a new click event handler:
$(this).find('.modal-yes').click(function(){
So if you show.bs.modal twice, then you have two click event handlers both submitting the AJAX request. Instead, just bind the click event handler once to the target clickable element, instead of binding it every time the modal is displayed.
Replace this:
$('#templateConfirmDialog').on('show.bs.modal', function (event) {
$(this).find('.modal-yes').click(function(){
//...
});
});
With this:
$('#templateConfirmDialog').find('.modal-yes').click(function(){
//...
});
Or, if that element is dynamically added to the DOM, this:
$(document).on('click', '#templateConfirmDialog .modal-yes', function(){
//...
});
That way there's just a single click event handler created when the page loads, rather than adding a new handler every time you display the modal.

Can I continue with a previous prevent link?

I have this link:
$('.popup-window').click(function (e) {
e.preventDefault();
$.ajax({
...
})
});
which is a .NET LinkButton (a link that call a javascript, not a real href). I want to prevent Default if ajax return some (let say, false). Else, if true, continue with that link handler.
How can I do it?
P.S. I need that e.preventDefault(); at the beginning, else .NET handler will act immediatly.

You can use the __doPostBack() js function to trigger the postback in your AJAX callback.
The only thing is that you need to pass in the id of the control causing the postback, e.g.
__doPostBack('btnPopup', null);
you can see more on this function in this question: How to use __doPostBack()

I think I understand what you're looking for.
Here's my idea on it: use a data attribute on the DOM element to decide weither default event should be prevented or not. Initially, the event is prevented but the ajax has the power to "unlock?" it, then fire it again. It's a little bit of custom work but it may do the trick:
var $popupWindow=$('popup-window');
// initially "tell" the LinkButton to prevent default
$popupWindow.data('prevent-default', 1);
// the click event (initially prevents default)
$popupWindow.click(function(e){
var $this=$(this);
if ($this.data('prevent-default')==0) { // if "unlocked"
// "lock" it again (default isn't prevented)
$this.data('prevent-default', 1);
} else { // if "locked"
// default is prevented
e.preventDefault();
// test if it should be unlocked
$.ajax({
// ...
}).done(function(data){
if (data.length>0 && data.response==false) {
// set the attribute so it shouldn't prevent default
$this.data('prevent-default', 0);
// trigger this click (should let the event fire completely)
$this.trigger('click');
}
});
}
});
UPDATE:
An alternative could be to add a Page Method.
(See: Using jQuery to directly call ASP.NET AJAX page methods)
This would reduce the mechanics to somethink like this:
$('popup-window').click(function(e){
e.preventDefault();
$.ajax({
// ...
}).done(function(data){
if (data.length>0 && data.response==false) {
$.ajax({
type: "POST",
url: "YourPage.aspx/YourMethod",
data: "{}",
contentType: "application/json; charset=utf-8",
dataType: "json",
success: function(msg) {
// Replace the div's content with the page method's return.
$("#Result").text(msg.d);
}
});
}
});
});

$('.popup-window').click(function (e) {
data = '?sample=1' //serialized data here
callback = function(json){
if(json.returnVar!=true){ //check if returnVar is not true
e.preventDefault(); //prevent redirect if not true
}
};
$.ajax({
type: 'POST',
url: "../ajaxcall.php", //the url to call for ajax here
data: data,
success: callback,
dataType: 'json'
});
});
Try this, let me know if you can't understand the code

values won't get updated in a function because of a ajax call

I'm writing a javascript function that should change the view of a postcard depending on which case is selected.
My problem is that the old values of the object "m_case" is getting used. If I press the button with class "case-btn" twice I get the right case selected in my postcard view. But I want it to be triggered when I press the button once.
I guess I have to do something like a callback function in the m_case.setCase() function call, but I can't get it working,
$('.case-btn').on('click', function() {
remove_active_state_from_cases();
m_case.setCase($(this).data('case'));
// Changes the view of the postcard
m_postcard.changeBackground(m_case.getPhoto());
m_postcard.changeMessage(m_case.getMessageText());
m_postcard.changeFullName(m_case.getFullName());
m_postcard.changeCountry(m_case.getCountry());
$(this).toggleClass('active');
});
The setCase() function
this.setCase = function(id) {
// Set ID
this.setID(id);
var that = this;
$.ajax({
url: 'get_case_by_id.php',
type: 'get',
dataType: 'json',
data: {id: that.getID() },
success: function(data) {
if(data.success) {
that.setFirstName(data.first_name);
that.setFullName(data.full_name);
that.setAdress(data.adress);
that.setCountry(data.country);
that.setStamp(data.stamp);
that.setPhoto(data.photo);
that.setSummary(data.summary);
that.setStory(data.story);
that.setMessageText(data.message_text);
that.setDefaultMessageText(data.default_message_text);
that.setMessageImg(data.message_img);
} else {
console.log('failure');
}
}
EDIT The problem might be in my AJAX call, I have to wait till the ajax have been called. but how do I continue the first flow when my Ajax is done and not before?
SOLUTION
I made it working by adding a callback parameter and calling that function in the ajaxs complete function.
$('.case-btn').on('click', function() {
remove_active_state_from_cases();
var that = this;
m_case.setCase($(this).data('case'), function() {
m_postcard.changeBackground(m_case.getPhoto());
m_postcard.changeMessage(m_case.getMessageText());
m_postcard.changeFullName(m_case.getFullName());
m_postcard.changeCountry(m_case.getCountry());
$(that).toggleClass('active');
});
});
// Sets the whole case from an id.
this.setCase = function(id, callback) {
// Set ID
this.setID(id);
var that = this;
$.ajax({
url: 'get_case_by_id.php',
type: 'get',
dataType: 'json',
data: {id: that.getID() },
success: function(data) {
if(data.success) {
that.setFirstName(data.first_name);
that.setFullName(data.full_name);
that.setAdress(data.adress);
that.setCountry(data.country);
that.setStamp(data.stamp);
that.setPhoto(data.photo);
that.setSummary(data.summary);
that.setStory(data.story);
that.setMessageText(data.message_text);
that.setDefaultMessageText(data.default_message_text);
that.setMessageImg(data.message_img);
} else {
console.log('fail big time');
}
},
complete: function() {
callback();
}
});
}

Your m_postcard.changeBackground and other calls should be in the success callback, or in another function that is called from the success callback, as those values aren't set till the async ajax call is done.
With the way your code is now the m_postcard.changeBackground and other calls are called immediately after your setCase function is done executing. This means your methods are executed before the data has arrived from the server
While the ajax is processing you probably should show a loading message on the screen to let the user know they have to wait till the processing is done. Show the message before calling the .ajax call and hide it in the success/error callbacks.
Any changes to the site content should be done from the success callback, ie changing active states, changing content, etc.

jQuery: How to apply a function to all elements including some which are loaded later via Ajax?

I have a simple jQuery function that resizes text areas, and I want it to apply to all text areas.
For the most part, this works great:
$(document.ready(function(){$("text_area").resizer('250px')});
However, because it is only called once when the document is ready, it fails to catch text areas that are later added onto the page using Ajax. I looked at the .live() function, which seems very close to what I'm looking. However, .live() must be bound to a specific event, whereas I just need this to fire once when they're done loading (the onLoad event doesn't work for individual elements).
The only thing I can get working is a really obtrusive inclusion of the JavaScript call directly into the Ajax. Is that the recommended way to be doing this?
Edit: Here is the rails source code for what it does for Ajax requests:
$('a[data-confirm], a[data-method], a[data-remote]').live('click.rails', function(e) {
var link = $(this);
if (!allowAction(link)) return false;
if (link.attr('data-remote') != undefined) {
handleRemote(link);
return false;
} else if (link.attr('data-method')) {
handleMethod(link);
return false;
}
});
// Submits "remote" forms and links with ajax
function handleRemote(element) {
var method, url, data,
dataType = element.attr('data-type') || ($.ajaxSettings && $.ajaxSettings.dataType);
if (element.is('form')) {
method = element.attr('method');
url = element.attr('action');
data = element.serializeArray();
// memoized value from clicked submit button
var button = element.data('ujs:submit-button');
if (button) {
data.push(button);
element.data('ujs:submit-button', null);
}
} else {
method = element.attr('data-method');
url = element.attr('href');
data = null;
}
$.ajax({
url: url, type: method || 'GET', data: data, dataType: dataType,
// stopping the "ajax:beforeSend" event will cancel the ajax request
beforeSend: function(xhr, settings) {
if (settings.dataType === undefined) {
xhr.setRequestHeader('accept', '*/*;q=0.5, ' + settings.accepts.script);
}
return fire(element, 'ajax:beforeSend', [xhr, settings]);
},
success: function(data, status, xhr) {
element.trigger('ajax:success', [data, status, xhr]);
},
complete: function(xhr, status) {
element.trigger('ajax:complete', [xhr, status]);
},
error: function(xhr, status, error) {
element.trigger('ajax:error', [xhr, status, error]);
}
});
}
So in my particular case, I've got a link, that has data-remote set to true, which points to a location that will return JavaScript instructing a form containing a text area to be appended to my document.

A simple way to do this would be to use ajaxComplete, which is fired after every AJAX request:
$(document).ajaxComplete(function() {
$('textarea:not(.processed)').resizer('250px');
});
That says "every time an AJAX request completes, find all textarea elements that don't have the processed class (which seems to be added by the resizer plugin -- terrible name for its purpose!) and call the resizer plugin on them.
You may be able to optimise this further if we could see your AJAX call.

Generally speaking, I would do it this way..
$.ajax({
type : "GET",
url : "/loadstuff",
success: function(responseHtml) {
var div = $("#containerDiv").append(responseHtml);
$("textarea", div).resizer("250px");
}
});

Wondering if you could use .load for this. For example:
$('text_area').load(function() {
$("text_area").resizer('250px');
});

jquery click event

I have some jquery that looks like this,
$('.career_select .selectitems').click(function(){
var selectedCareer = $(this).attr('title');
$.ajax({
type: 'POST',
url: '/roadmap/step_two',
data: 'career_choice='+selectedCareer+"&ajax=true&submit_career=Next",
success: function(html){
$('.hfeed').append(html);
$('#grade_choice').SelectCustomizer();
}
});
});
My problem is that if the user keeps clicking then the .hfeed keeps getting data appended to it. How can I limit it so that it can only be clicked once?

Use the one function:
Attach a handler to an event for the elements. The handler is executed at most once per element
If you wanted the element to only be clicked once and then be re-enabled once the request finishes, you could:
A) Keep a state variable that updates if a request is currently in progress and exits at the top of the event if it is.
B) Use one, put your code inside a function, and rebind upon completion of request.
The second option would look like this:
function myClickEvent() {
var selectedCareer = $(this).attr('title');
var that = this;
$.ajax({
type: 'POST',
url: '/roadmap/step_two',
data: 'career_choice='+selectedCareer+"&ajax=true&submit_career=Next",
success: function(html){
$('.hfeed').append(html);
$('#grade_choice').SelectCustomizer();
},
complete: function() {
$(that).one('click', myClickEvent);
}
});
}
$('.career_select .selectitems').one('click', myClickEvent);

You can either use a global variable like
var added = false;
$('.career_select .selectitems').click(function(){
if(!added) {
// previous code here
added = true;
}
});
or use .one("click", function () { ... }) instead of the previous click function to execute the handler at most once per element. See http://api.jquery.com/one/ for more details.