Ajax request fails on window unload - javascript

I have a scenario where I need to make a cross-domain request upon leaving a page. The endpoint has all the proper CORS headers configured.
This is the request:
$.ajax({
type: "POST",
url: URL,
data: {
// some stuff
},
async: false
});
When tested as-is, it works great. When I try to trigger this request from an unload handler:
$(window).unload(function() {
// same as above
});
it intermittently fails. On the occasion that it fails, I get this stack trace:
Error: A network error occurred.
at Object.x.ajaxTransport.x.support.cors.e.crossDomain.send (http://cdnjs.cloudflare.com/ajax/libs/jquery/2.0.3/jquery.min.js:6:9344)
at Function.x.extend.ajax (http://cdnjs.cloudflare.com/ajax/libs/jquery/2.0.3/jquery.min.js:6:4804)
at http://my.web.site.com/main.js:129:11
at x.event.dispatch (http://cdnjs.cloudflare.com/ajax/libs/jquery/2.0.3/jquery.min.js:5:10006)
at x.event.add.y.handle (http://cdnjs.cloudflare.com/ajax/libs/jquery/2.0.3/jquery.min.js:5:6789)
With a jQuery DOMException and error code 19.
What's going on here? It looks like there's some race condition here that I'm unaware of, but other than setting the request to be synchronous, I'm not sure what else I can do.

You simply can't rely on unload handlers. May it be jQuery's implementation or the native onbeforeunload. (Maybe onbeforeunload will work better then jQuery's implementation)
There are so many ways a user can leave the page (crash, ALT+F4, close tab, ...).
Most browsers just don't wait long enough, so your async requests will fail in most cases.
You should probably reconsider your design.

I ended up using the beforeunload event instead:
$(window).on('beforeunload' function() {
// same code
});
which works just fine on all modern browsers. The beforeunload event behavior is consistent, and as long as the request is sent out synchronously, the event execution - and thus the window unloading - is paused.
This is the exact event services such as Gmail, Facebook and even Stack Overflow use to confirm is user is genuinely interested in leaving a page while in the middle of an action.

Related

Fetch API before the user closes the browser is not behaving consistently [duplicate]

I'm trying to find out when a user left a specified page. There is no problem finding out when he used a link inside the page to navigate away but I kind of need to mark up something like when he closed the window or typed another URL and pressed enter. The second one is not so important but the first one is. So here is the question:
How can I see when a user closed my page (capture window.close event), and then... doesn't really matter (I need to send an AJAX request, but if I can get it to run an alert, I can do the rest).
Updated 2021
TL;DR
Beacon API is the solution to this issue (on almost every browser).
A beacon request is supposed to complete even if the user exits the page.
When should you trigger your Beacon request ?
This will depend on your usecase. If you are looking to catch any user exit, visibilitychange (not unload) is the last event reliably observable by developers in modern browsers.
NB: As long as implementation of visibilitychange is not consistent across browsers, you can detect it via the lifecycle.js library.
# lifecycle.js (1K) for cross-browser compatibility
# https://github.com/GoogleChromeLabs/page-lifecycle
<script defer src="/path/to/lifecycle.js"></script>
<script defer>
lifecycle.addEventListener('statechange', function(event) {
if (event.originalEvent == 'visibilitychange' && event.newState == 'hidden') {
var url = "https://example.com/foo";
var data = "bar";
navigator.sendBeacon(url, data);
}
});
</script>
Details
Beacon requests are supposed to run to completion even if the user leaves the page - switches to another app, etc - without blocking user workflow.
Under the hood, it sends a POST request along with the user credentials (cookies), subject to CORS restrictions.
var url = "https://example.com/foo";
var data = "bar";
navigator.sendBeacon(url, data);
The question is when to send your Beacon request. Especially if you want to wait until the last moment to send session info, app state, analytics, etc.
It used to be common practice to send it during the unload event, but changes to page lifecycle management - driven by mobile UX - killed this approach. Today, most mobile workflows (switching to new tab, switching to the homescreen, switching to another app...) do not trigger the unload event.
If you want to do things when a user exits your app/page, it is now recommended to use the visibilitychange event and check for transitioning from passive to hidden state.
document.addEventListener('visibilitychange', function() {
if (document.visibilityState == 'hidden') {
// send beacon request
}
});
The transition to hidden is often the last state change that's reliably observable by developers (this is especially true on mobile, as users can close tabs or the browser app itself, and the beforeunload, pagehide, and unload events are not fired in those cases).
This means you should treat the hidden state as the likely end to the user's session. In other words, persist any unsaved application state and send any unsent analytics data.
Details of the Page lifecyle API are explained in this article.
However, implementation of the visibilitychange event, as well as the Page lifecycle API is not consistent across browsers.
Until browser implementation catches up, using the lifecycle.js library and page lifecycle best practices seems like a good solution.
# lifecycle.js (1K) for cross-browser compatibility
# https://github.com/GoogleChromeLabs/page-lifecycle
<script defer src="/path/to/lifecycle.js"></script>
<script defer>
lifecycle.addEventListener('statechange', function(event) {
if (event.originalEvent == 'visibilitychange' && event.newState == 'hidden') {
var url = "https://example.com/foo";
var data = "bar";
navigator.sendBeacon(url, data);
}
});
</script>
For more numbers about the reliability of vanilla page lifecycle events (without lifecycle.js), there is also this study.
Adblockers
Adblockers seem to have options that block sendBeacon requests.
Cross site requests
Beacon requests are POST requests that include cookies and are subject to CORS spec. More info.
There are unload and beforeunload javascript events, but these are not reliable for an Ajax request (it is not guaranteed that a request initiated in one of these events will reach the server).
Therefore, doing this is highly not recommended, and you should look for an alternative.
If you definitely need this, consider a "ping"-style solution. Send a request every minute basically telling the server "I'm still here". Then, if the server doesn't receive such a request for more than two minutes (you have to take into account latencies etc.), you consider the client offline.
Another solution would be to use unload or beforeunload to do a Sjax request (Synchronous JavaScript And XML), but this is completely not recommended. Doing this will basically freeze the user's browser until the request is complete, which they will not like (even if the request takes little time).
1) If you're looking for a way to work in all browsers, then the safest way is to send a synchronous AJAX to the server. It is is not a good method, but at least make sure that you are not sending too much of data to the server, and the server is fast.
2) You can also use an asynchronous AJAX request, and use ignore_user_abort function on the server (if you're using PHP). However ignore_user_abort depends a lot on server configuration. Make sure you test it well.
3) For modern browsers you should not send an AJAX request. You should use the new navigator.sendBeacon method to send data to the server asynchronously, and without blocking the loading of the next page. Since you're wanting to send data to server before user moves out of the page, you can use this method in a unload event handler.
$(window).on('unload', function() {
var fd = new FormData();
fd.append('ajax_data', 22);
navigator.sendBeacon('ajax.php', fd);
});
There also seems to be a polyfill for sendBeacon. It resorts to sending a synchronous AJAX if method is not natively available.
IMPORTANT FOR MOBILE DEVICES : Please note that unload event handler is not guaranteed to be fired for mobiles. But the visibilitychange event is guaranteed to be fired. So for mobile devices, your data collection code may need a bit of tweaking.
You may refer to my blog article for the code implementation of all the 3 ways.
I also wanted to achieve the same functionality & came across this answer from Felix(it is not guaranteed that a request initiated in one of these events will reach the server).
To make the request reach to the server we tried below code:-
onbeforeunload = function() {
//Your code goes here.
return "";
}
We are using IE browser & now when user closes the browser then he gets the confirmation dialogue because of return ""; & waits for user's confirmation & this waiting time makes the request to reach the server.
Years after posting the question I made a way better implementation including nodejs and socket.io (https://socket.io) (you can use any kind of socket for that matter but that was my personal choice).
Basically I open up a connection with the client, and when it hangs up I just save data / do whatever I need. Obviously this cannot be use to show anything / redirect the client (since you are doing it server side), but is what I actually needed back then.
io.on('connection', function(socket){
socket.on('disconnect', function(){
// Do stuff here
});
});
So... nowadays I think this would be a better (although harder to implement because you need node, socket, etc., but is not that hard; should take like 30 min or so if you do it first time) approach than the unload version.
The selected answer is correct that you can't guarantee that the browser sends the xhr request, but depending on the browser, you can reliably send a request on tab or window close.
Normally, the browser closes before xhr.send() actually executes. Chrome and edge look like they wait for the javascript event loop to empty before closing the window. They also fire the xhr request in a different thread than the javascript event loop. This means that if you can keep the event loop full for long enough, the xhr will successfully fire. For example, I tested sending an xhr request, then counting to 100,000,000. This worked very consistently in both chrome and edge for me. If you're using angularjs, wrapping your call to $http in $apply accomplishes the same thing.
IE seems to be a little different. I don't think IE waits for the event loop to empty, or even for the current stack frame to empty. While it will occasionally correctly send a request, what seems to happen far more often (80%-90% of the time) is that IE will close the window or tab before the xhr request has completely executed, which result in only a partial message being sent. Basically the server receives a post request, but there's no body.
For posterity, here's the code I used attached as the window.onbeforeunload listener function:
var xhr = new XMLHttpRequest();
xhr.open("POST", <your url here>);
xhr.setRequestHeader("Content-Type", "application/json;charset=UTF-8");
var payload = {id: "123456789"};
xhr.send(JSON.stringify(payload));
for(var i = 0; i < 100000000; i++) {}
I tested in:
Chrome 61.0.3163.100
IE 11.608.15063.0CO
Edge 40.15063.0.0
Try this one. I solved this problem in javascript, sending ajax call to server on browse or tab closing. I had a problem with refreshing page because on onbeforeunload function including refreshing of the page. performance.navigation.type == 1 should isolate refresh from closing (on mozzila browser).
$(window).bind('mouseover', (function () { // detecting DOM elements
window.onbeforeunload = null;
}));
$(window).bind('mouseout', (function () { //Detecting event out of DOM
window.onbeforeunload = ConfirmLeave;
}));
function ConfirmLeave() {
if (performance.navigation.type == 1) { //detecting refresh page(doesnt work on every browser)
}
else {
logOutUser();
}
}
$(document).bind('keydown', function (e) { //detecting alt+F4 closing
if (e.altKey && e.keyCode == 115) {
logOutUser();
}
});
function logOutUser() {
$.ajax({
type: "POST",
url: GWA("LogIn/ForcedClosing"), //example controller/method
async: false
});
}
Im agree with Felix idea and I have solved my problem with that solution and now I wanna to clear the Server Side solution:
1.send a request from client side to server
2.save time of the last request recived in a variable
3.check the server time and compare it by the variable of last recived
request
4.if the result is more than the time you expect,start running the
code you want to run when windows closed...
Use:
<body onUnload="javascript:">
It should capture everything except shutting down the browser program.

Angular 6: Trying to make synchronous call (delete) on browser close event (beforeunload/unload event of browser)

Actually, I want to update a flag in Db using a service call(Delete method) once the user close the browser. I am able to detect browser close action using onbeforeunload and onunload events but async call doesn't work for me(sometimes in debugging mode it works fine but on higher env it doesn't work).
Then, I tried to make sync request but then I found that Chrome now disallows synchronous XHR during page dismissal when the page is being navigated away from or closed by the user.
check link : https://www.chromestatus.com/feature/4664843055398912
I have tried new XMLHttpRequest() as sync, fetch api also Navigator.sendBeacon() but unfortunately nothing works for me.
Please suggest something which works because I have visited so many posts but nothing works for me.
Thanks in advance.
I have some solution for this. Hope so any one of them solves your issue.
constructor() {
window.onbeforeunload = ()=>{
//call API here
}
}
In your component constructor write above code
OR
In my opinion the better idea is making the heartbeat api that sends requests every N seconds to notify server that the session is active and the user is online. On the server check every M minutes if there was no heartbeat requests for more than N seconds: if it is so - execute the API request(what you wanted to execute on crash).
OR
'beforeunload' would be trigger when refreshing pages, closing tab, or closing the browser.
#HostListener('window:beforeunload', ['$event'])
beforeUnload(e: Event) {
e.returnValue = false;
}
OR
It is not possible to ensure that every time an user exits a browser page a specific function will be triggered. The reason is that the browser could close the window for many reasons. Yes it could be a user action but this is not the only case. For example The browser could crash.
In my case I will have to find another strategy to track the time the user stays on the page. For example I am planning to send a lot of API calls before the user exits with all the informations I need to understand his stay on the page. I will update the answer when I will reach a good solution. Anyway I will still wait for better answers.
You can use the fetch API.
The syntax would be:
fetch('API', {
method: 'POST', // Other opn are also supported like GET,PUT DELETE
body: '',
keepalive: true
});
Just an additional read:
https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API

Can beforeunload/unload be used to send XmlHttpRequests reliably

recently, I had the urgent requirement to give my server a notice, that a specific page of my webapp is about to get closed. "Easy peasy" I thought, beforeunload is available for quite a while. The HTML5 "thing" even refreshed the spec (that was what I thought...) about it, in the way that we had the option to return a string value from a beforeunload event handler and stuff, which gives an user the option to intercept.
See the MDN page about onbeforeunload
However, as it turned out, there isn't any "official" specification available, which describes the behavior for beforeunload up to this date. The only official document I found, was on WHATWG, which is just a proposal for W3C of course.
See WHATWG
So far so good. We are able to create a synchronized XHR request within a beforeunload event handler. "Most" browsers, give that request a timeframe of about 1-2 seconds to complete, after that it is getting killed. Standard asynchronous request are killed immediately. Having that said, I cannot even tell from "where" I know this, it seems like gossip and word of mouth looking at it now. Even tho, it works in Firefox+Chrome, we cannot rely on that, can we ?
Is there any ongoing discussion/proposal on WHATWG about beforeunload ?
Any other official resources about the event I might have not found ?
And far most important to me here, how reliably can we send data via sync-XHR there ?
Take a look at navigator.sendBeacon(), which allows you to reliably send data to a server even when the page is unloading. It's currently in a draft specification and supported by Firefox 31, Chrome 39 (behind a flag from 37), behind a flag in Opera 24.
You could "sort of" polyfill it using something like the following:
navigator.sendBeacon = navigator.sendBeacon || function (url, data) {
var xhr = new XMLHttpRequest();
// Need to send synchronously to have the best chance of data getting
// through to the server
xhr.open('POST', url, false);
xhr.send(data);
};
Further reading:
HTML5 Rocks article
The thing to keep in mind is that beforeunload started as an extension by Internet Explorer. Automatically, that makes it a second-class citizen on the web. There is no specification, and browser implementation varies. For example, Firefox only partially implements it by not displaying the string, only a generic message.
Additionally, even when fully implemented, it does not protect against all possible unload scenarios, eg, the user has terminated the processor, the browser has crashed, or the computer has been turned off. Even ignoring these extreme scenarios, I suspect that it might be possible to configure your browser to ignore such requests.
My feeling is that you shouldn't rely on this message to save you. If this web app is internal, I would suggest training them to use the Save or Close or whatever buttons instead of just closing the tab. If it's external, maybe look into automatic saving as the user does their thing?
Sync XHR is a top-source of browser hangs, accounting for nearly 10% of hangs: http://blogs.msdn.com/b/ieinternals/archive/2011/08/03/do-not-use-xmlhttprequest-in-synchronous-mode-unless-you-like-to-hang.aspx
In IE, even sync XHR can be "interrupted" if the request requires Windows authentication roundtrips, or if there's a POST body to be sent. You may find that only the headers of the first unauthenticated request are sent.

JQuery Ajax post parameters sometimes not sent on IE

The problem I am having is that when I use jquery ajax post, with very low frequency (< 2%), the post parameters never make it to the server. I do see the post request in the access log. It seems to happen only on IE (I've observed it on 7, 8, and 9 in the logs).
When I switch the call from type "post" to type "get" the issue goes away.
Has anyone else ever seen this odd behavior on IE? Thanks!
I have seen this for various ajax calls, but here is a typical one:
var data= {
"guess" : "m1",
"eas" : "hello world"
};
$.ajax({
url: "http://myco.com/ajaxcall.action",
data: data,
type : 'post',
dataType: 'json',
success: function(data) {},
error: function() {}
});
Update: passing "cache: false" does not fix the issue.
I have spent the last week tracking down a similar problem in my own application (uses Dojo, not JQuery). From your description and frequency of occurrence, I would say it's the same issue.
When HTTP persistent connections are used between browser and server (the default behavior), an HTTP connection can be closed down by the server at any time. This creates a very small timing hole when the browser starts to send a new request at the same time the server closes the connection. Most browsers will use a different connection or open a new connection and resend the request. This is the behavior suggested in RFC 2616 section 8.1.4:
A client, server, or proxy MAY close the transport connection at any
time. For example, a client might have started to send a new request
at the same time that the server has decided to close the "idle"
connection. From the server's point of view, the connection is being
closed while it was idle, but from the client's point of view, a
request is in progress.
This means that clients, servers, and proxies MUST be able to recover
from asynchronous close events. Client software SHOULD reopen the
transport connection and retransmit the aborted sequence of requests
without user interaction so long as the request sequence is
idempotent (see section 9.1.2).
Internet explorer does try to resend the request when this happens, but when it happens to be a POST, it mangles it up by sending the headers (with Content-Length) but no actual data. That is a malformed request and should always lead to an HTTP error (usually after some timeout waiting for the data that never comes).
This bug is documented by Microsoft as KB 895954 (see http://support.microsoft.com/kb/895954). Microsoft first recognized this bug in IE 6. They provided a hotfix, and appear to have shipped the hotfix with every version of IE since then including IE 9. There are two problems with the fix:
The hotfix is not activated by default. You have to create a really weird key using regedit to activate the fix: HKEY_LOCAL_MACHINE\Software\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_SKIP_POST_RETRY_ON_INTERNETWRITEFILE_KB895954.
The fix doesn't really fix the problem. The "fixed" behavior is that when the connection is closed when trying to send a request, it does not even try to resend it. It simply passes the error along to the javascript application.
It appears that you have to add error handlers in your code and re-post the request yourself if it fails. I am looking into this solution for my application. My concern is that I'm not sure how to tell if the error I get is caused by a failed attempt to send the query, or some error sent back from the server as a result of the query (in which case I don't want to resend it).
I wrote a C program to simulate a web server and explicitly close a connection to see how the browser handles it. I have found that IE reproduces the errant behavior 100% of the time, while Firefox, Safari and Chrome recover by properly resending the POST on another connection 100% of the time. Perhaps the answer is, "don't use IE."
As a direct answer to your question: Yes we have just come across this issue and could not find a reasonable explanation. It only affects IE and with a very low frequency - took a long while to get to the conclusion that it is a sporadic jQuery Ajax in IE bug. We had to 'fix' the issue by returning a fail from the server under this condition and re-posting the data after a 1 second delay!
Hacky as hell but seemed to be the only way.
There was definitely no clash with DOM elements etc. and no logical reason for this to happen, the page can be updated many times by the user successfully with intermittent fails.
Must be a bug.
I think you have to prevent caching in Internet Explorer. Try to set option cache to false.
Example:
$.ajax({
url: "http://myco.com/ajaxcall.action",
data: data,
type : 'post',
dataType: 'json',
success: function(data) {},
error: function() {},
cache: false
});
The params sent to the PHP are received from IE in GET:
$.ajax ({
url: "path/to/ajax.php"
,method: "POST"
,data: {
var1: "value1"
,var2: true
,varX: 123123
}
,cache: false
,success: function (data) {
alert (data);
}
});
Then on PHP you should use REQUEST instead of POST:
$var1 = $_REQUEST ["var1"]; // value1
$var2 = $_REQUEST ["var2"]; // true
$var3 = $_REQUEST ["var3"]; // 123123
This example could use it for compatibility with IE7

JavaScript, browsers, window close - send an AJAX request or run a script on window closing

I'm trying to find out when a user left a specified page. There is no problem finding out when he used a link inside the page to navigate away but I kind of need to mark up something like when he closed the window or typed another URL and pressed enter. The second one is not so important but the first one is. So here is the question:
How can I see when a user closed my page (capture window.close event), and then... doesn't really matter (I need to send an AJAX request, but if I can get it to run an alert, I can do the rest).
Updated 2021
TL;DR
Beacon API is the solution to this issue (on almost every browser).
A beacon request is supposed to complete even if the user exits the page.
When should you trigger your Beacon request ?
This will depend on your usecase. If you are looking to catch any user exit, visibilitychange (not unload) is the last event reliably observable by developers in modern browsers.
NB: As long as implementation of visibilitychange is not consistent across browsers, you can detect it via the lifecycle.js library.
# lifecycle.js (1K) for cross-browser compatibility
# https://github.com/GoogleChromeLabs/page-lifecycle
<script defer src="/path/to/lifecycle.js"></script>
<script defer>
lifecycle.addEventListener('statechange', function(event) {
if (event.originalEvent == 'visibilitychange' && event.newState == 'hidden') {
var url = "https://example.com/foo";
var data = "bar";
navigator.sendBeacon(url, data);
}
});
</script>
Details
Beacon requests are supposed to run to completion even if the user leaves the page - switches to another app, etc - without blocking user workflow.
Under the hood, it sends a POST request along with the user credentials (cookies), subject to CORS restrictions.
var url = "https://example.com/foo";
var data = "bar";
navigator.sendBeacon(url, data);
The question is when to send your Beacon request. Especially if you want to wait until the last moment to send session info, app state, analytics, etc.
It used to be common practice to send it during the unload event, but changes to page lifecycle management - driven by mobile UX - killed this approach. Today, most mobile workflows (switching to new tab, switching to the homescreen, switching to another app...) do not trigger the unload event.
If you want to do things when a user exits your app/page, it is now recommended to use the visibilitychange event and check for transitioning from passive to hidden state.
document.addEventListener('visibilitychange', function() {
if (document.visibilityState == 'hidden') {
// send beacon request
}
});
The transition to hidden is often the last state change that's reliably observable by developers (this is especially true on mobile, as users can close tabs or the browser app itself, and the beforeunload, pagehide, and unload events are not fired in those cases).
This means you should treat the hidden state as the likely end to the user's session. In other words, persist any unsaved application state and send any unsent analytics data.
Details of the Page lifecyle API are explained in this article.
However, implementation of the visibilitychange event, as well as the Page lifecycle API is not consistent across browsers.
Until browser implementation catches up, using the lifecycle.js library and page lifecycle best practices seems like a good solution.
# lifecycle.js (1K) for cross-browser compatibility
# https://github.com/GoogleChromeLabs/page-lifecycle
<script defer src="/path/to/lifecycle.js"></script>
<script defer>
lifecycle.addEventListener('statechange', function(event) {
if (event.originalEvent == 'visibilitychange' && event.newState == 'hidden') {
var url = "https://example.com/foo";
var data = "bar";
navigator.sendBeacon(url, data);
}
});
</script>
For more numbers about the reliability of vanilla page lifecycle events (without lifecycle.js), there is also this study.
Adblockers
Adblockers seem to have options that block sendBeacon requests.
Cross site requests
Beacon requests are POST requests that include cookies and are subject to CORS spec. More info.
There are unload and beforeunload javascript events, but these are not reliable for an Ajax request (it is not guaranteed that a request initiated in one of these events will reach the server).
Therefore, doing this is highly not recommended, and you should look for an alternative.
If you definitely need this, consider a "ping"-style solution. Send a request every minute basically telling the server "I'm still here". Then, if the server doesn't receive such a request for more than two minutes (you have to take into account latencies etc.), you consider the client offline.
Another solution would be to use unload or beforeunload to do a Sjax request (Synchronous JavaScript And XML), but this is completely not recommended. Doing this will basically freeze the user's browser until the request is complete, which they will not like (even if the request takes little time).
1) If you're looking for a way to work in all browsers, then the safest way is to send a synchronous AJAX to the server. It is is not a good method, but at least make sure that you are not sending too much of data to the server, and the server is fast.
2) You can also use an asynchronous AJAX request, and use ignore_user_abort function on the server (if you're using PHP). However ignore_user_abort depends a lot on server configuration. Make sure you test it well.
3) For modern browsers you should not send an AJAX request. You should use the new navigator.sendBeacon method to send data to the server asynchronously, and without blocking the loading of the next page. Since you're wanting to send data to server before user moves out of the page, you can use this method in a unload event handler.
$(window).on('unload', function() {
var fd = new FormData();
fd.append('ajax_data', 22);
navigator.sendBeacon('ajax.php', fd);
});
There also seems to be a polyfill for sendBeacon. It resorts to sending a synchronous AJAX if method is not natively available.
IMPORTANT FOR MOBILE DEVICES : Please note that unload event handler is not guaranteed to be fired for mobiles. But the visibilitychange event is guaranteed to be fired. So for mobile devices, your data collection code may need a bit of tweaking.
You may refer to my blog article for the code implementation of all the 3 ways.
I also wanted to achieve the same functionality & came across this answer from Felix(it is not guaranteed that a request initiated in one of these events will reach the server).
To make the request reach to the server we tried below code:-
onbeforeunload = function() {
//Your code goes here.
return "";
}
We are using IE browser & now when user closes the browser then he gets the confirmation dialogue because of return ""; & waits for user's confirmation & this waiting time makes the request to reach the server.
Years after posting the question I made a way better implementation including nodejs and socket.io (https://socket.io) (you can use any kind of socket for that matter but that was my personal choice).
Basically I open up a connection with the client, and when it hangs up I just save data / do whatever I need. Obviously this cannot be use to show anything / redirect the client (since you are doing it server side), but is what I actually needed back then.
io.on('connection', function(socket){
socket.on('disconnect', function(){
// Do stuff here
});
});
So... nowadays I think this would be a better (although harder to implement because you need node, socket, etc., but is not that hard; should take like 30 min or so if you do it first time) approach than the unload version.
The selected answer is correct that you can't guarantee that the browser sends the xhr request, but depending on the browser, you can reliably send a request on tab or window close.
Normally, the browser closes before xhr.send() actually executes. Chrome and edge look like they wait for the javascript event loop to empty before closing the window. They also fire the xhr request in a different thread than the javascript event loop. This means that if you can keep the event loop full for long enough, the xhr will successfully fire. For example, I tested sending an xhr request, then counting to 100,000,000. This worked very consistently in both chrome and edge for me. If you're using angularjs, wrapping your call to $http in $apply accomplishes the same thing.
IE seems to be a little different. I don't think IE waits for the event loop to empty, or even for the current stack frame to empty. While it will occasionally correctly send a request, what seems to happen far more often (80%-90% of the time) is that IE will close the window or tab before the xhr request has completely executed, which result in only a partial message being sent. Basically the server receives a post request, but there's no body.
For posterity, here's the code I used attached as the window.onbeforeunload listener function:
var xhr = new XMLHttpRequest();
xhr.open("POST", <your url here>);
xhr.setRequestHeader("Content-Type", "application/json;charset=UTF-8");
var payload = {id: "123456789"};
xhr.send(JSON.stringify(payload));
for(var i = 0; i < 100000000; i++) {}
I tested in:
Chrome 61.0.3163.100
IE 11.608.15063.0CO
Edge 40.15063.0.0
Try this one. I solved this problem in javascript, sending ajax call to server on browse or tab closing. I had a problem with refreshing page because on onbeforeunload function including refreshing of the page. performance.navigation.type == 1 should isolate refresh from closing (on mozzila browser).
$(window).bind('mouseover', (function () { // detecting DOM elements
window.onbeforeunload = null;
}));
$(window).bind('mouseout', (function () { //Detecting event out of DOM
window.onbeforeunload = ConfirmLeave;
}));
function ConfirmLeave() {
if (performance.navigation.type == 1) { //detecting refresh page(doesnt work on every browser)
}
else {
logOutUser();
}
}
$(document).bind('keydown', function (e) { //detecting alt+F4 closing
if (e.altKey && e.keyCode == 115) {
logOutUser();
}
});
function logOutUser() {
$.ajax({
type: "POST",
url: GWA("LogIn/ForcedClosing"), //example controller/method
async: false
});
}
Im agree with Felix idea and I have solved my problem with that solution and now I wanna to clear the Server Side solution:
1.send a request from client side to server
2.save time of the last request recived in a variable
3.check the server time and compare it by the variable of last recived
request
4.if the result is more than the time you expect,start running the
code you want to run when windows closed...
Use:
<body onUnload="javascript:">
It should capture everything except shutting down the browser program.

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