I'm wondering whether there's a simple way to delay the click event from being processed for a specified period of time. For example we could have
$('#someElement').on('click', 'a', function(event) {
var duration = 1000;
someAsynchronousFunction(); // Start as soon as click occurs
... // Code to delay page transition from taking place for duration specified
});
So in this case the asynchronous function would be guaranteed some amount of time to run. If it hasn't completed it's work in this time I wouldn't care and would just like to continue with the page transition. I know that it's possible to accomplish something close with
event.preventDefault();
...
setTimeout(function(){
window.location = $(this).attr('href');
}, duration);
But this only works when the link being clicked goes to a full page. I want to be able to deal with links that are used for ajax calls (which don't change the url) as well.
I noticed that the mixpanel library has a function track_links which seems to accomplish the delay on the page transition, though that function doesn't seem to work well with the support for ajax links that I mentioned.
Any help would be great! Thanks.
Edit: So I suppose my question wasn't exactly clear, so I'll try to provide some more details below.
I don't care if the async function finishes running! I only want to give it the guarantee that it has some set amount of time to execute, after which I don't care if it finishes, and would prefer to go ahead with the page transition.
i.e. I want to delay not the start of the async function, but the start of the page transition. The async function would start running as soon as the click occured.
Hopefully this is a bit more clear!
I figured out a way to solve the problem:
var secondClick = false;
var duration = 1000;
$('#someElement').on('click', 'a', function(event) {
var that = $(this);
if(!secondClick) {
event.stopPropagation();
setTimeout(function(){
secondClick = true;
that.click();
}, duration);
someAsynchronousFunction();
} else {
secondClick = false;
}
});
When the user clicks the link, it internally prevents that click from actually having any effect, and gives the asynchronous function a set amount of time to do it's work before doing a second click on the link which behaves normally.
setTimeout allows you to delay running code by however many ms you want
setTimeout(function(){
console.log('Stuff be done'); //This will be delayed for one second
}, 1000);
In reality, if you're dealing with ajax you want to respond when the ajax call is complete. It may take more or less than 1000ms. $.ajax allows you do this with the .done() method. This is an example from the docs:
$.ajax({
url: "test.html",
context: document.body
}).done(function() {
$(this).addClass("done");
});
window.setTimeout will execute any given function after a specified delay.
You'd call it like this:
$('yourElement').click(function (event) {
setTimeout(function () { console.log('hi'); }, 1000);
});
But I have to wonder why you need to do this. What's the problem you're trying to solve? Usually delaying stuff doesn't really solve anything.
jQuery's ajax functionality provides exactly what you are looking for. You can define a callback function to run after your ajax request.
Something like this:
$('#someElement').click(function(event){
event.preventDefault();
var loc = $(this).attr('href');
$.ajax({
url: "test.html",
complete: function(){
// Handle the complete event
loc = $(this).attr('href');
window.location.href = loc;
}
});
});
You may want to use ajaxStop instead of complete, it seems like your motivation for delaying navigation is because you have a bunch of asynchronous stuff going on and you want to make sure all your ajax stuff is complete before you navigate to that page.
Regardless I would recommend looking at http://api.jquery.com/Ajax_Events/ (a very useful page of documentation).
Related
I'm trying to make a spinner button that will spin while I make an AJAX request and stop when the answer is received.
I've got the AJAX handled but the spinning doesn't seem to work with the following code:
function refresh (id){
var iconElem = document.getElementById("spinner" + id);
iconElem.classList.add('fa-spin');
sleep(5000);
var buttonRefresh = document.getElementById("refreshButton" + id);
buttonRefresh.classList.remove("fa-spin");
};
Note : I have replaced the ajax function with a sleep (implemented elsewhere, but it works like like it should) since I am in a non-php environment.
What happens here is that the the class "fa-spin" is being added while the sleep is over, even though it comes after in the code... Am I missing some kind of "refresh" that I need to execute in order to make the added class effective ?
You need to stop the spinning in the completion callback of the ajax call as it is a async call.
What you are doing here is starting and then immediately stopping the spinner before the ajax call even finishes.
$.ajax({
url: "test.html",
cache: false,
success: function(html){
// stop the spinner here
}
});
Here is the simplest solution with a callback:
function sleep(callback,timeout){
setTimeout(callback,timeout)
}
sleep(() => {
//stop spinner here
},200)
Anyways, I suggest you to read more here
If you are doing an ajax request, you can also use the async:false header to make your request synced, and then your code should work.
Changes to the style or content of the document become effective only when the JavaScript function finishes and returns to the main event loop. Therefore, assuming your sleep() function works as expected (by doing a busy wait or something like that, although that is not actually sleeping), you can only see the total effect of all changes when the function returns. If you follow the advice of the other answers and remove the style in the callback of the AJAX call, you will be fine.
You'll have to forgive me if I show any kind of ineptitude here, jquery and java isn't my usual area of work. But here goes:
I have a page that shows a random list of items that are pulled from a server using an API call. The idea is that every time the user clicks "generate" a new list is produced and inserted into the page. This works but it's very fast and all the user sees is a list rapidly changing. To spruce things up I've decided to put some nice animations and effects in.
I've got a jquery function that loops through each element in the list of child elements and toggles the css style of the child element so that an effect from the animate.css library is applied. The problem is when I have another function that loads the new list and this is called immediately and therefore all of the css transitions are ignored; or rather they don't get a chance to run because the second method immediately triggers.
I've tried using a callback and had no joy, I've tried using deferred objects. No luck at all.
Here's the code I have so far:
function removeOldContent() {
$('#removableContent > div').each(function (index) {
var elm = $(this);
setTimeout(function () {
elm.toggleClass('customAnim', function () {
$(this).remove();
});
}, index * 150);
});
}
function getList() {
var rId = $('.tab-content').find('.active').data('d-id');
var serviceUrl = '/GetRandom/GetList';
$.ajax({
type: 'POST',
url: serviceUrl,
data: {
reportId : rId
},
success: function(data) {
$('#reportContainer').html(data).fadeIn('slow');
}
});
}
Ideally I'd like to be able to let removeOldContent() finish completely, after all the timeouts have run. And then trigger getList() to update the content. I'll work on making a nice transition for the inbound data but first I just need to get this working.
Any advice or pointers would be greatly appreciated.
***** Update ******
I've made a fiddle. Not giving me the same error as my dev env but should be close enough for you to see
https://jsfiddle.net/rdt1pfhk/9/
Your problem is with the timing of events. Your removeOldContent function uses a setTimeout function which in turn animates and removes the items from the DOM. Your getList() function was executing before the other function had finished. I put a quick untidy solution together using your fiddle. I return a jquery deferred object from you removeOldContent method and then only call the getList when that is resolved (and the older items removed from the dom). It is not the neatest but it will point you in the right direction. I updated your fiddle here: https://jsfiddle.net/rdt1pfhk/16/
function removeOldContent() {
var deferred = new jQuery.Deferred();
....
return deferred;
}
$(document).on('click', '.quickPick', function (e) {
removeOldContent().then(function(){
getList();
});
});
If I understood correctly you need to only delay some functions for as long as you need. I think the answer you are looking for could be found here:
How to delay calling of javascript function?
Also, I'd like to mention that I don't see a
$(document).ready(function () {
//your code here
});
anywhere. Maybe I'm wrong but since you mentioned that CSS is ignored, are you sure the page is loaded before your code starts being executed?
In my web application, I'm using an $.ajax() request to load data from a database and display it in the browser. During the execution of the request, I display a Loading Results ... message like this:
$.ajax({
// ...
beforeSend: function() {
$('#loading-results-message').show();
},
complete: function() {
$('#loading-results-message').hide();
}
});
This works fine. However, if there is not much data to load, the request takes only a fraction of a second. In this case, the message is only displayed for a fraction of a second as well. This animation happens so quickly that it's difficult to recognize it. Therefore, it would be great if it was possible to display the message only if the request takes a certain amount of time, i.e. some seconds at least but not only a fraction of a second. Is that possible somehow? By the way, I'm using Django on the server side, if that should matter.
Use setTimeout to establish a timer, cancel the timer when the request completes:
var desired_delay = 2000;
var message_timer = false;
$.ajax({
// ...
beforeSend: function() {
message_timer = setTimeout(function () {
$('#loading-results-message').show();
message_timer = false;
}, desired_delay);
},
complete: function() {
if (message_timer)
clearTimeout(message_timer);
message_timer = false;
$('#loading-results-message').hide();
}
});
Documentation
setTimeout on MDN - https://developer.mozilla.org/en-US/docs/DOM/window.setTimeout
clearTimeout on MDN - https://developer.mozilla.org/en-US/docs/DOM/window.clearTimeout
I am with #chris on this solution. But it might also be worth your while to look into http://api.jquery.com/jQuery.ajaxSetup/
This will make it so you won't have to write the timeout for every single request.
We're creating a click tracking app, that builds heatmaps. I'm writing a script which users are suppose to insert into their pages for tracking to work.
It works fine on elements, which doesn't require a redirect or form submit. For example, if I click on h1 or p or whatever, it works perfectly correct. But, if I click on a a, request to our server never happens before the normal redirect.
In the last couple of days I tried a lot of ways to do that. First of, I tried a normal AJAX call, since it was a cross-domain request I had to use JSONP, but again, that AJAX call did not have time to execute before the redirect. Adding async: false would have solved the problem, but it doesn't work with JSONP requests. So I decided to add a flag variable which indicates that it is safe to move on with redirect and used an empty while loop to wait until it becomes try in the ajax callback. But the while loop was blocking the execution flow, so callback never got a chance to set that variable to true. Here is some simplified code:
$(document).on('click', function (e) {
//part of the code is omitted
$.ajax({
url: baseUrl,
data: data,
type: "get",
dataType: "jsonp",
crossDomain: true,
complete: function (xhr, status,) {
itsSafeToMoveOn = true;
}
});
while(!itsSafeToMoveOn){}
return true;
});
The next thing I tried is to use unload page event to wait until total ajax calls in progress would become zero (I had a counter implemented) and then to move on with redirect. It worked in Firefox and IE, but in WebKit there was this error:
Error: Too much time spent in unload handler
After that I realized that I don't care about the server response and using img.src for the request would be an ideal fit for this case. So at this point code looks like this:
$(document).click(function (e) {
//part of the code is ommited
(new Image).src = baseUrl + '?' + data;
if (tag === "a" || clickedElement.parents().has("a")) {
sleep(100);
}
return true;
});
That way I increased the overall script performance slightly, but problem with links remains unchanged. The sleep function appears to be also blocking the execution flow and request never happens.
The only idea left is to return false from the event handler and than redirect manually to the clicked element's href or to call submit() on the form, but it will complicate things to much and believe me it's already a huge pain in the ass to debug this script in different browsers.
Does anyone have any other ideas?
var globalStopper = true;
$(document).on('click', function (e) {
if (globalStopper === false)
return true; //proceed with click if stopper is NOT set
else {
globalStopper = false; //release the breaks
$.ajax({
//blahblah
complete: function (xhr, status,) {
$(elem).click(); //when ajax request done - "rerun" the click
}
});
return false; //DO NOT let browser process the click
}
});
Also, instead of adding image, try adding script. And then add the script to the HEAD section. This way the browser will "wait" until it's loaded.
$(document).on('click', function (e) {
var scriptTag = document.createElement("script");
scriptTag.setAttribute("type", "text/javascript");
scriptTag.setAttribute("src", url);
document.getElementsByTagName("head")[0].appendChild(scriptTag);
return true;
}
I would take a look at the navigator sendBeacon API mentioned in this stack overflow answer or directly linked to here.
From the description on the site
navigator.sendBeacon(url, data) - This method addresses the needs of analytics and diagnostics code that typically attempts to send data to a web server prior to the unloading of the document.
You can save information to ajax request in cookies or localStorage and make any worker that will send information. Saving to cookies or localStorage is faster then ajax-request. You can do next:
$(document).click(function (e) {
var queue = localStorage.getItem('requestQueue');
queue.push(data);
localStorage.setItem('requestQueue',queue);
});
$(function(){
setInterval(function(){
var queue = localStorage.getItem('requestQueue');
while (queue.length > 0) {
var data = queue.pop();
$.ajax({
...
success: function(){
localStorage.setItem('requestQueue', queue);
}
});
}
},intervalToSendData);
});
So, when user click on link or send a form, data will be saved to storage and after user go to next page, this worker starts and send data to your server.
The JavaScript is basically executed in single thread. It is not possible to have your callback function executed and at the same time have an infinite loop waiting for a flag variable from it. The infinite loop will occupy the single execution thread and the callback will never be called.
Best approach is to cancel the default handler of your event and bubbling for it (basically return false if you are really building your tracking code with jQuery), and do the necessary actions (redirect page to the necessary address if a link was clicked or trigger other default actions), but this would take a lot of careful work to recreate all the possible combinations of actiona and callbacks.
Another approach is to:
1) Look for something specific to your code in the event data
2) If it is not present - make an AJAX call and in its callback re-trigger the same even on the same element, but this time with your specific bit added to the even data; after the AJAX call return false
3) If your specific bits are present in the data - simply do nothing, allowing the default event processing to take place.
The either approach may bite, however.
So if I understand right, you want your ajax logs completed before the page unloads and follows a link href. This sounds like a perfect case where you could consider using Deferreds in jQuery.
When your user clicks on anything that's supposed to take him away from the page, just check your promise status. If it's not resolved, you could throw a modal window over the page, and ask the user to wait til the progress is complete. Then, add a new pipe to your deferred, telling it to change the location href once everything is complete.
Let me know if this is the scenario. If it is, I'll explain in more detail. No use continuing if I didn't understand your requirement properly
I have a text box on a web page, whose value I want to send to a XMLHttpRequest. Now I want the user to just type the value, without pressing a button. But If i just send the request int he keyboard events, it will fire every time a key is pressed.
So basically I want something liek this
function KeyUpEvent()
{
if (user is still typing)
return;
else
//do processing
}
It would be great if the solution could come from plain javascript or mootools. I dont want to use any other library.
The way this is usually done is by restarting a timer on the keyup event. Something like this:
var keyupTimer;
function keyUpEvent(){
clearTimeout(keyupTimer);
keyupTimer = setTimeout(sendInput,1000); // will activate when the user has stopped typing for 1 second
}
function sendInput(){
alert("Do AJAX request");
}
Basically, you want to start a timer on KeyUp, and when KeyUp starts again, reset the timer. When the user stops typing, the timer runs out, and your request can go at that point.
Example:
var timout_id;
function keyup_handler(event) {
if (timout_id) {
clearTimeout(timout_id);
}
timout_id = setTimeout(function(){
alert('sending data: \n' + event.target.value)
}, 800);
}
Just attach the function to the input using your preferred method, and replace the alert with your preferred action.
Of course there are many ways you could generalize this approach and make it more reusable, etc, but I think this illustrates the basic idea.
I always use this simple function to handle a timer, that will fire a callback function, after the user has stopped typing for a specified amount of time:
var typewatch = (function(){
var timer = 0;
return function(callback, ms){
clearTimeout (timer);
timer = setTimeout(callback, ms);
}
})();
Usage (example with MooTools):
$('textInput').addEvent('keyup', function(e){
typewatch(function () {
// executed only 500 ms after the last keyup event
// make Ajax request
}, 500);
});
The main difference between this solution and solutions from other answers is that all the timer logic is handled by the typewatch function itself, the event handler doesn't need to know anything about the timer, it just invokes the function. Also, there are no global variables to take care (the timer id is not stored on a global variable).
You never know when a user is really "finished" typing. The user might take a sneeze break, or a stretch break, or a coffee break, and then continue typing.
However, if you're implementing something like an autocomplete mechanism, you can set a timer (cf. window.setTimeout(...)) to see if the user hasn't typed anything in a certain amount of time. If you get another key-up event while the timer is running, you can start the timer over.
var keyTimer;
function onKeyUp(){
clearTimeout(keyTimer);
setTimeout(stoppedTyping,1500);
}
function stoppedTyping(){
// Profit! $$$
}
EDIT: Damn ninjas
I wrote a custom jQuery event because I use this logic a lot:
jQuery.event.special.stoppedtyping = {
setup: function(data, namespaces) {
jQuery(this).bind('keyup', jQuery.event.special.stoppedtyping.keyuphandler);
},
teardown: function(namespaces) {
jQuery(this).bind('keyup', jQuery.event.special.stoppedtyping.keyuphandler);
},
keyuphandler: function(e) {
var interval = 1000;
var el = this;
if (jQuery.data(this, 'checklastkeypress') != null) {
clearTimeout(jQuery.data(this, 'checklastkeypress'));
}
var id = setTimeout(function() {
jQuery(el).trigger('stoppedtyping');
}, interval);
jQuery.data(this, 'checklastkeypress', id);
}
};
You can use it like this:
$('input.title').bind('stoppedtyping', function() {
// run some ajax save operation
});
For some reason I could never get it to work with .live( ... ). I'm not sure why...
Use onBlur and maybe an onKeyDown to check for the user pressing the return/enter key.