Is it possible that using jQuery, I cancel/abort an Ajax request that I have not yet received the response from?
Most of the jQuery Ajax methods return an XMLHttpRequest (or the equivalent) object, so you can just use abort().
See the documentation:
abort Method (MSDN). Cancels the current HTTP request.
abort() (MDN). If the request has been sent already, this method will abort the request.
var xhr = $.ajax({
type: "POST",
url: "some.php",
data: "name=John&location=Boston",
success: function(msg){
alert( "Data Saved: " + msg );
}
});
//kill the request
xhr.abort()
UPDATE:
As of jQuery 1.5 the returned object is a wrapper for the native XMLHttpRequest object called jqXHR. This object appears to expose all of the native properties and methods so the above example still works. See The jqXHR Object (jQuery API documentation).
UPDATE 2:
As of jQuery 3, the ajax method now returns a promise with extra methods (like abort), so the above code still works, though the object being returned is not an xhr any more. See the 3.0 blog here.
UPDATE 3: xhr.abort() still works on jQuery 3.x. Don't assume the update 2 is correct. More info on jQuery Github repository.
You can't recall the request but you can set a timeout value after which the response will be ignored. See this page for jquery AJAX options. I believe that your error callback will be called if the timeout period is exceeded. There is already a default timeout on every AJAX request.
You can also use the abort() method on the request object but, while it will cause the client to stop listening for the event, it may probably will not stop the server from processing it.
Save the calls you make in an array, then call xhr.abort() on each.
HUGE CAVEAT: You can abort a request, but that's only the client side. The server side could still be processing the request. If you are using something like PHP or ASP with session data, the session data is locked until the ajax has finished. So, to allow the user to continue browsing the website, you have to call session_write_close(). This saves the session and unlocks it so that other pages waiting to continue will proceed. Without this, several pages can be waiting for the lock to be removed.
It's an asynchronous request, meaning once it's sent it's out there.
In case your server is starting a very expensive operation due to the AJAX request, the best you can do is open your server to listen for cancel requests, and send a separate AJAX request notifying the server to stop whatever it's doing.
Otherwise, simply ignore the AJAX response.
AJAX requests may not complete in the order they were started. Instead of aborting, you can choose to ignore all AJAX responses except for the most recent one:
Create a counter
Increment the counter when you initiate AJAX request
Use the current value of counter to "stamp" the request
In the success callback compare the stamp with the counter to check if it was the most recent request
Rough outline of code:
var xhrCount = 0;
function sendXHR() {
// sequence number for the current invocation of function
var seqNumber = ++xhrCount;
$.post("/echo/json/", { delay: Math.floor(Math.random() * 5) }, function() {
// this works because of the way closures work
if (seqNumber === xhrCount) {
console.log("Process the response");
} else {
console.log("Ignore the response");
}
});
}
sendXHR();
sendXHR();
sendXHR();
// AJAX requests complete in any order but only the last
// one will trigger "Process the response" message
Demo on jsFiddle
We just had to work around this problem and tested three different approaches.
does cancel the request as suggested by #meouw
execute all request but only processes the result of the last submit
prevents new requests as long as another one is still pending
var Ajax1 = {
call: function() {
if (typeof this.xhr !== 'undefined')
this.xhr.abort();
this.xhr = $.ajax({
url: 'your/long/running/request/path',
type: 'GET',
success: function(data) {
//process response
}
});
}
};
var Ajax2 = {
counter: 0,
call: function() {
var self = this,
seq = ++this.counter;
$.ajax({
url: 'your/long/running/request/path',
type: 'GET',
success: function(data) {
if (seq === self.counter) {
//process response
}
}
});
}
};
var Ajax3 = {
active: false,
call: function() {
if (this.active === false) {
this.active = true;
var self = this;
$.ajax({
url: 'your/long/running/request/path',
type: 'GET',
success: function(data) {
//process response
},
complete: function() {
self.active = false;
}
});
}
}
};
$(function() {
$('#button').click(function(e) {
Ajax3.call();
});
})
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<input id="button" type="button" value="click" />
In our case we decided to use approach #3 as it produces less load for the server. But I am not 100% sure if jQuery guarantees the call of the .complete()-method, this could produce a deadlock situation. In our tests we could not reproduce such a situation.
It is always best practice to do something like this.
var $request;
if ($request != null){
$request.abort();
$request = null;
}
$request = $.ajax({
type : "POST", //TODO: Must be changed to POST
url : "yourfile.php",
data : "data"
}).done(function(msg) {
alert(msg);
});
But it is much better if you check an if statement to check whether the ajax request is null or not.
Just call xhr.abort() whether it's jquery ajax object or native XMLHTTPRequest object.
example:
//jQuery ajax
$(document).ready(function(){
var xhr = $.get('/server');
setTimeout(function(){xhr.abort();}, 2000);
});
//native XMLHTTPRequest
var xhr = new XMLHttpRequest();
xhr.open('GET','/server',true);
xhr.send();
setTimeout(function(){xhr.abort();}, 2000);
You can abort any continuous ajax call by using this
<input id="searchbox" name="searchbox" type="text" />
<script src="http://code.jquery.com/jquery-1.11.0.min.js"></script>
<script type="text/javascript">
var request = null;
$('#searchbox').keyup(function () {
var id = $(this).val();
request = $.ajax({
type: "POST", //TODO: Must be changed to POST
url: "index.php",
data: {'id':id},
success: function () {
},
beforeSend: function () {
if (request !== null) {
request.abort();
}
}
});
});
</script>
As many people on the thread have noted, just because the request is aborted on the client-side, the server will still process the request. This creates unnecessary load on the server because it's doing work that we've quit listening to on the front-end.
The problem I was trying to solve (that others may run in to as well) is that when the user entered information in an input field, I wanted to fire off a request for a Google Instant type of feel.
To avoid firing unnecessary requests and to maintain the snappiness of the front-end, I did the following:
var xhrQueue = [];
var xhrCount = 0;
$('#search_q').keyup(function(){
xhrQueue.push(xhrCount);
setTimeout(function(){
xhrCount = ++xhrCount;
if (xhrCount === xhrQueue.length) {
// Fire Your XHR //
}
}, 150);
});
This will essentially send one request every 150ms (a variable that you can customize for your own needs). If you're having trouble understanding what exactly is happening here, log xhrCount and xhrQueue to the console just before the if block.
I was doing a live search solution and needed to cancel pending requests that may have taken longer than the latest/most current request.
In my case I used something like this:
//On document ready
var ajax_inprocess = false;
$(document).ajaxStart(function() {
ajax_inprocess = true;
});
$(document).ajaxStop(function() {
ajax_inprocess = false;
});
//Snippet from live search function
if (ajax_inprocess == true)
{
request.abort();
}
//Call for new request
Just use ajax.abort() for example you could abort any pending ajax request before sending another one like this
//check for existing ajax request
if(ajax){
ajax.abort();
}
//then you make another ajax request
$.ajax(
//your code here
);
there is no reliable way to do it, and I would not even try it, once the request is on the go; the only way to react reasonably is to ignore the response.
in most cases, it may happen in situations like: a user clicks too often on a button triggering many consecutive XHR, here you have many options, either block the button till XHR is returned, or dont even trigger new XHR while another is running hinting the user to lean back - or discard any pending XHR response but the recent.
The following code shows initiating as well as aborting an Ajax request:
function libAjax(){
var req;
function start(){
req = $.ajax({
url: '1.php',
success: function(data){
console.log(data)
}
});
}
function stop(){
req.abort();
}
return {start:start,stop:stop}
}
var obj = libAjax();
$(".go").click(function(){
obj.start();
})
$(".stop").click(function(){
obj.stop();
})
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<input type="button" class="go" value="GO!" >
<input type="button" class="stop" value="STOP!" >
If xhr.abort(); causes page reload,
Then you can set onreadystatechange before abort to prevent:
// ↓ prevent page reload by abort()
xhr.onreadystatechange = null;
// ↓ may cause page reload
xhr.abort();
I had the problem of polling and once the page was closed the poll continued so in my cause a user would miss an update as a mysql value was being set for the next 50 seconds after page closing, even though I killed the ajax request, I figured away around, using $_SESSION to set a var won't update in the poll its self until its ended and a new one has started, so what I did was set a value in my database as 0 = offpage , while I'm polling I query that row and return false; when it's 0 as querying in polling will get you current values obviously...
I hope this helped
I have shared a demo that demonstrates how to cancel an AJAX request-- if data is not returned from the server within a predefined wait time.
HTML :
<div id="info"></div>
JS CODE:
var isDataReceived= false, waitTime= 1000;
$(function() {
// Ajax request sent.
var xhr= $.ajax({
url: 'http://api.joind.in/v2.1/talks/10889',
data: {
format: 'json'
},
dataType: 'jsonp',
success: function(data) {
isDataReceived= true;
$('#info').text(data.talks[0].talk_title);
},
type: 'GET'
});
// Cancel ajax request if data is not loaded within 1sec.
setTimeout(function(){
if(!isDataReceived)
xhr.abort();
},waitTime);
});
This is my implementation based on many answers above:
var activeRequest = false; //global var
var filters = {...};
apply_filters(filters);
//function triggering the ajax request
function apply_filters(filters){
//prepare data and other functionalities
var data = {};
//limit the ajax calls
if (activeRequest === false){
activeRequest = true;
}else{
//abort if another ajax call is pending
$request.abort();
//just to be sure the ajax didn't complete before and activeRequest it's already false
activeRequest = true;
}
$request = $.ajax({
url : window.location.origin + '/your-url.php',
data: data,
type:'POST',
beforeSend: function(){
$('#ajax-loader-custom').show();
$('#blur-on-loading').addClass('blur');
},
success:function(data_filters){
data_filters = $.parseJSON(data_filters);
if( data_filters.posts ) {
$(document).find('#multiple-products ul.products li:last-child').after(data_filters.posts).fadeIn();
}
else{
return;
}
$('#ajax-loader-custom').fadeOut();
},
complete: function() {
activeRequest = false;
}
});
}
I wanted to make an ajax call, and then wait for the response from ajax call (Stop form submission till then) and then post the form based on the ajax response that I get. This question is based on Make ajax call and then submit form. So, after putting below script, everything works fine, but I lose the client side validation. Can I make an ajax call and still respect the Client Side validation?
#section scripts {
<script>
var canSubmit = false;
$('form').submit(function (e) {
if (!canSubmit) {
e.preventDefault();
var data = $('form').serialize();
var url = $(this).data('url');
$.ajax({
url: url,
type: 'POST',
data: data,
success: function (response) {
if (response.hasPreviousRequest) {
if (confirm("You've already applied for this job. Apply again?")) {
canSubmit = true;
$('form').submit();
}
}
else {
canSubmit = true;
$('form').submit();
}
},
error: function () {
alert("error");
}
});
}
});
</script>
}
P.S: Kindly note that as soon I as remove the ajax call Client side validation starts working fine. Can some one please explain me this behaviour?
You need to call the .valid() method on the form element (and if not, then cancel the ajax call)
$('form').submit(function (e) {
if (!$(this).valid()) {
return // exit
}
if (!canSubmit) {
....
I've looked around and none of the other similar posts have helped me. I have built an AJAx based form in Yii 2 and jQuery and it seems it submits the form twice.
My form:
$form = ActiveForm::begin([
'id' => 'company_form',
'ajaxDataType' => 'json',
'ajaxParam' => 'ajax',
'enableClientValidation' => false
]);
My JS code:
$(document).ready(function() {
/* Processes the company signup request */
$('#company_form').submit(function() {
signup('company');
return false;
});
})
function signup(type) {
var url;
// Set file to get results from..
switch (type) {
case 'company':
url = '/site/company-signup';
break;
case 'client':
url = '/site/client-signup';
break;
}
// Set parameters
var dataObject = $('#company_form').serialize();
// Run request
getAjaxData(url, dataObject, 'POST', 'json')
.done(function(response) {
//.........
})
.fail(function() {
//.....
});
// End
}
Shouldn't the standard submit be stopped by me putting the return: false; in the javascript code?
Why is it submitting twice?
More Info: However the strange thing is, that only appears to happen the first time; if I hit submit again it only submits once; but if I reload the page and hit submit it will do it twice again.
You may need to change your code like below:
$('#company_form').submit(function(e) {
e.preventDefault();
e.stopImmediatePropagation();
signup('company');
return false;
});
http://api.jquery.com/event.stoppropagation/
http://api.jquery.com/event.stopimmediatepropagation/
Solution common
Next JS will works with any state of 'enableClientValidation':
$('#company_form').on('beforeSubmit', function (e) {
signup('company');
return false;
});
https://yii2-cookbook.readthedocs.io/forms-activeform-js/#using-events
I've got some JS which works in Chrome, but not in FireFox, and I'm too inexperienced in JS to be able to troubleshoot this without some assistance.
I tested it from localhost on my dev machine and from its deployed location (on our internal intranet) ... same results in both cases.
In chrome, it does exactly what I expect. It asynchronously catches a JSON object from the API and splashes it for the user.
In FF, it takes the user to the target API URL. No "asynchronisity".
What tweaks can I do to support FF too??
(fortunately, FF & Chm are the only two I need to code against).
Any and all help will be greatly appreciated.
var submit_map_url = 'blahblah'; // dynamically generated by PHP
$('#mapper_form').submit(function() {
event.preventDefault();
$.ajax({
type:'POST',
url: submit_map_url,
data:$('#mapper_form').serialize(),
success: function(response) {
var response = $.parseJSON(response);
if(response.status == 'failure'){
alert(response.message);
}else{
var doRedirect = true;
$('#splash').fadeIn(800, function() { // fade in
window.setTimeout ( function() { // start a timer for auto redirect
$('#splash').fadeOut(1000, function() { // fade out
if(doRedirect) window.location = redirect_target; // then redirect
}) }
, 4000); //
});
$('#splash').click(function(){ // on click
doRedirect = false; // cancel the redirect request
$(this).fadeOut(700,function() {}); // and fade out
});
$('#countdown').countdown({until: +5, format: 'S'});
} // end IF/ELSE
} // end success:
}); // ajax
return false;
});
Add the event parameter to you submit function. $('#mapper_form').submit(function(event) {
Chrome has a global event object window.event when you are in a event handler.
I have the following code build using jquery. When a user copies and pastes a a youtube url, i am suppose to extract the video id is the getVideoId(str) method in jquery. Using the id, i get the video image picture title and contents.
When the textbox->("#url") has a length more than 10, i will make a ajax request. Thus the ajax request is working. But now i have another problem. The very first time when the textbox has more than 10 characters, there is two ajax request being fired (tested using firebug). Than when the user enters more characters, there are many ajax request fired.
Thus this will slow down the process of the last ajax request. I just want to get the data of the youtube link and show a suggest where the user can add the title and content. It is like how the old facebook video video link is. Anyone has a better suggest in improving the codes?
jQuery(document).ready(
function(){
$("#url").keyup(function() {
var $t1 = $("#url").val();
var $length = $t1.length;
var $data;
$("#title").val($length);
$("#content").val($t1);
if($length==0){
alert('zero value');
return;
}
if($length>10){
$data = $.ajax({
url: '<?php echo $this->Html->url(array("action" => "retrieveVideoFeed"));?>',
dataType: "json",
data: {
vid: getVideoId($t1)
},
success: function(data) {
alert('success in getting data');
}
});
return;
}
});
function getVideoId(str) {
var urlRegex = /(http|https):\/\/(\w+:{0,1}\w*#)?(\S+)(:[0-9]+)?(\/|\/([\w#!:.?+=&%#!\-\/]))?/;
if (urlRegex.test(str) && str.indexOf('v=') != -1)
{
return str.split('v=')[1].substr(0, 11); // get 11-char youtube video id
} else if (str.length == 11) {
return str;
}
return null;
}
}
);
You could cache the calls and use blur event and not keyup: you are firing a lot of AJAX call because keyup() fires an event each time a key is pressed, you should use blur that fires an event when an input loses focus.
If you cache the calls in an object you can avoid a lot of repeated calls
var cacheUrl = {};
$("#url").blur(function() {
var $t1 = $("#url").val();
var $length = $t1.length;
var $data;
$("#title").val($length);
$("#content").val($t1);
if($length==0){
alert('zero value');
return;
}
if(cacheUrls[$t1] !== undefined && $length>10){
$data = $.ajax({
url: '<?php echo $this->Html->url(array("action" => "retrieveVideoFeed"));?>',
dataType: "json",
data: {
vid: getVideoId($t1)
},
success: function(data) {
//save the data to avoid a future call
cacheUrls[$t1] = data;
alert('success in getting data');
}
});
return;
}elseif ($length>10){
//you already have the data in cacheUrls[$t1]
}
});
EDIT if you want to use the submit key to start the search you could trigger the blur event when you press enter like this:
$("#url").keypress(function(e){
if(e.which == 13){
$(this).blur();
return false;
}
});
I think many ajax requests are fired because you are using $("#url").keyup(function()
so that for every key event in url input the particular funciton will exectue.So, as per i know better to use focusout method instead of keyup.
If you stay with the keyup-Event you maybe want to use an ajaxmanager-plugin for jQuery which can manage queues or limits the number of simultaneous requests.
$.manageAjax.create('myAjaxManager', {
queue: true,
cacheResponse: false,
maxRequests: 1,
queue: 'clear'
});
....
if($length>10){
$data = $.manageAjax.add({ ...
This will prevent having alot of ajaxrequests active at the same time when the user is typing. As soon as he stops the request will not aborted and the results will show up.