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Is there a way to run a final JavaScript code when a user closes a browser window or refreshes the page?
I'm thinking of something similar to onload but more like onclose? Thanks.
I don't like the onbeforeunload method, which always yields to a confirmation box popping up (leave page/ stay on mozilla) or (reload/ don't reload on chrome). Is there a way to execute the code quietly?
There is both window.onbeforeunload and window.onunload, which are used differently depending on the browser. You can assign them either by setting the window properties to functions, or using the .addEventListener:
window.onbeforeunload = function(){
// Do something
}
// OR
window.addEventListener("beforeunload", function(e){
// Do something
}, false);
Usually, onbeforeunload is used if you need to stop the user from leaving the page (ex. the user is working on some unsaved data, so he/she should save before leaving). onunload isn't supported by Opera, as far as I know, but you could always set both.
Ok, I found a working solution for this, it consists of using the beforeunload event and then making the handler return null. This executes the wanted code without a confirmation box popping-up. It goes something like this:
window.onbeforeunload = closingCode;
function closingCode(){
// do something...
return null;
}
Sometimes you may want to let the server know that the user is leaving the page. This is useful, for example, to clean up unsaved images stored temporarily on the server, to mark that user as "offline", or to log when they are done their session.
Historically, you would send an AJAX request in the beforeunload function, however this has two problems. If you send an asynchronous request, there is no guarantee that the request would be executed correctly. If you send a synchronous request, it is more reliable, but the browser would hang until the request has finished. If this is a slow request, this would be a huge inconvenience to the user.
Later came navigator.sendBeacon(). By using the sendBeacon() method, the data is transmitted asynchronously to the web server when the User Agent has an opportunity to do so, without delaying the unload or affecting the performance of the next navigation. This solves all of the problems with submission of analytics data: the data is sent reliably, it's sent asynchronously, and it doesn't impact the loading of the next page.
Unless you are targeting only desktop users, sendBeacon() should not be used with unload or beforeunload since these do not reliably fire on mobile devices. Instead you can listen to the visibilitychange event. This event will fire every time your page is visible and the user switches tabs, switches apps, goes to the home screen, answers a phone call, navigates away from the page, closes the tab, refreshes, etc.
Here is an example of its usage:
document.addEventListener('visibilitychange', function() {
if (document.visibilityState == 'hidden') {
navigator.sendBeacon("/log.php", analyticsData);
}
});
When the user returns to the page, document.visibilityState will change to 'visible', so you can also handle that event as well.
sendBeacon() is supported in:
Edge 14
Firefox 31
Chrome 39
Safari 11.1
Opera 26
iOS Safari 11.4
It is NOT currently supported in:
Internet Explorer
Opera Mini
Here is a polyfill for sendBeacon() in case you need to add support for unsupported browsers. If the method is not available in the browser, it will send a synchronous AJAX request instead.
Update:
It might be worth mentioning that sendBeacon() only sends POST requests. If you need to send a request using any other method, an alternative would be to use the fetch API with the keepalive flag set to true, which causes it to behave the same way as sendBeacon(). Browser support for the fetch API is about the same.
fetch(url, {
method: ...,
body: ...,
headers: ...,
credentials: 'include',
mode: 'no-cors',
keepalive: true,
})
jQuery version:
$(window).unload(function(){
// Do Something
});
Update: jQuery 3:
$(window).on("unload", function(e) {
// Do Something
});
Thanks Garrett
The documentation here encourages listening to the onbeforeunload event and/or adding an event listener on window.
window.addEventListener('beforeunload', function(event) {
//do something here
}, false);
You can also just populate the .onunload or .onbeforeunload properties of window with a function or a function reference.
Though behaviour is not standardized across browsers, the function may return a value that the browser will display when confirming whether to leave the page.
You can use window.onbeforeunload.
window.onbeforeunload = confirmExit;
function confirmExit(){
alert("confirm exit is being called");
return false;
}
The event is called beforeunload, so you can assign a function to window.onbeforeunload.
Is there a way to execute the code quietly? (no popup)
I have used this successfully, where other methods (eg returning null or false) had issues. Tested on ie, Edge, Chrome, Opera.
window.addEventListener('beforeunload', function (e) {
// the absence of a returnValue property on the event will guarantee the browser unload happens
delete e['returnValue'];
// my code that silently runs goes here
});
The above code is pasted directly from Mozilla.org's onbeforeunload doc
Update: This doesn't appear to work on IOS Safari :( So not a total solution, but maybe it still helps someone.
I am trying to do an API call when the user is trying to close/reload the browser/tab. I don't want to call the API if the user clicks on cancel. I followed JavaScript, browsers, window close - send an AJAX request or run a script on window closing, but it didn't solve my issue. I followed catching beforeunload confirmation canceled? for differentiating between confirm and cancel. I have no idea how to make the API call when the user reloads/closes the browser and not to call the API when user clicks on cancel. I followed JavaScript, browsers, window close - send an AJAX request or run a script on window closing and tried like
For showing alert on reload or close the tab
<script>
window.addEventListener("onbeforeunload", function(evt){
evt.preventDefault()
const string = '';
evt.returnValue = string;
return string;
})
</script>
and on click of cancel, nothing should happen. If the user is forcefully closing the browser or reloading, the API should be called
<script type="module">
import lifecycle from 'https://cdn.rawgit.com/GoogleChromeLabs/page-lifecycle/0.1.1/dist/lifecycle.mjs';
lifecycle.addEventListener('statechange', function(event) {
if (event.originalEvent === 'visibilitychange' && event.newState === 'hidden') {
var URL = "https://api.com/" //url;
var data = '' //payload;
navigator.sendBeacon(URL, data);
}
});
</script>
But it's not happening. Any help is appreciated. Thanks
Your problem is happening because you're using beforeunload to present a prompt.
I can see that you're handling the beforeunload event properly, so you must already be aware that browser vendors have deliberately limited the ability of script authors to do custom stuff when the user wants to leave the page. This is to prevent abuse.
Part of that limitation is that you don't get to find out what the user decides to do. And there will not be any clever workarounds, either. Once you tell the browser to present the beforeunload prompt, you lose all your power. If the user clicks the Okay button (i.e. decides to leave the page), the browser will refuse to run any more of your code.
Presenting the prompt creates a fork in the road that you are prevented from observing. So, put a laser tripwire there instead of a fork:
window.addEventListener("onbeforeunload", function(evt) {
navigator.sendBeacon(url, payload)
})
This is guaranteed to run when the user actually leaves the page, and only when the user actually leaves the page. But, you sacrifice the ability to try to talk the user out of leaving. You can't have it both ways.
You can't always get what you want, but if you try, sometimes you just might find you get what you need. -- The Rolling Stones
I can only think of one way to accomplish what you need, but it requires help from the server. This is not an option for most people (usually because the beacon goes to a third-party analytics provider who won't do this), but I'm including it here for completeness.
before the beforeunload handler returns, fire a beacon message that says "user is maybe leaving the page"
after firing that beacon, and still before returning, set up a document-wide mousemove handler that fires a second beacon message that says "the user is still here" (and also de-registers itself)
return false to present the prompt
modify your server so that it will reconcile these two events after some kind of delay:
if the server receives beacon 1 and then also receives beacon 2 (within some reasonably short time-frame, e.g. 5 minutes), it means the user tried to leave but then changed their mind, and so the server should delete the record of beacon 1
if the server receives beacon 1 but doesn't receive beacon 2 within the time-frame, then it means the user really did leave, and so the server would rewrite the previous beacon datapoint to say "user actually departed"; you wouldn't need to actually write beacon 2 to your datastore
(Or, depending on expected traffic and your infrastructure, maybe the server just holds the beacon 1 datapoint in RAM for the 5 minutes and commits it to your datastore only if beacon 2 never shows up. Or you could write both beacons to the database and then have a different process reconcile the beacons later. The outcome is identical, but they have different performance characteristics and resource requirements.)
P.S.: Never use "URL" (all caps) as a variable name in javascript. "URL" is actually a useful web API, so if you use that exact variable name, you're clobbering a useful ability. It's just like if you did let navigator = 'Henry'. Yes, it will execute without error, but it shadows a useful native capability.
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.
I want to implement an idle time-out for the web application that we are building. I had earlier achieved this using AsynchronousSessionAuditor from codeplex, which essentially looks for the formsauthentication and session cookie timeout by constant polling.
But it has a draw back of not respecting the client side events, it will look for only last postback to decide when to log off.
The jquery plug jquery-idle-timeout-plugin from erichynds solves this issue of client side events but suffers from another drawback that is not able to recognise user is active on some other tab.
Is there anyone already fixed the TABBED browsing issue with jquery-idle-timeout-plugin already? Or is there any better approach of application time out for web applications (by the way this web app is build using asp.net f/w)
If I understand your question right, it is not possible, since there are no events triggered in javascript for activity outside of the current window/tab.
Unless you have a addon to go along with your website for each browser, which could monitor all activity in the browser, but that is not really a practical approach.
Well, you'd have to code it by hand, which is not really hard. You can use the onfocus and onblur functions to do something like this:
$(function() {
window.isActive = true;
$(window).focus(function() { this.isActive = true; });
$(window).blur(function() { this.isActive = false; });
showIsActive();
});
function showIsActive()
{
console.log(window.isActive)
window.setTimeout("showIsActive()", 2000);
}
function doWork()
{
if (!window.isActive) { /* Check for idle time */}
}
If you make a little search you can find that varaieties of this question have already been asked and answered, you can probably find a solution you can implement with one of the plugins you mentioned.
Try:
Run setTimeout only when tab is active
or
How to tell if browser/tab is active
EDIT--> ADDED:
Or I'd try a different approach. You could create a cookie with some hash and save that hash in your DB with a timestamp that updates whenever the window is active (you could check every 5 seconds or something, it's not an intensive request)
Then, do another check before(but in the same request) to see how much time has passed since the last timestamp and log them out if necessary.
it won't log them out isntantly when time has passed, but it will when they try to access the site either by opening it again or by focusing on the tab/window.
Is there a way to run a final JavaScript code when a user closes a browser window or refreshes the page?
I'm thinking of something similar to onload but more like onclose? Thanks.
I don't like the onbeforeunload method, which always yields to a confirmation box popping up (leave page/ stay on mozilla) or (reload/ don't reload on chrome). Is there a way to execute the code quietly?
There is both window.onbeforeunload and window.onunload, which are used differently depending on the browser. You can assign them either by setting the window properties to functions, or using the .addEventListener:
window.onbeforeunload = function(){
// Do something
}
// OR
window.addEventListener("beforeunload", function(e){
// Do something
}, false);
Usually, onbeforeunload is used if you need to stop the user from leaving the page (ex. the user is working on some unsaved data, so he/she should save before leaving). onunload isn't supported by Opera, as far as I know, but you could always set both.
Ok, I found a working solution for this, it consists of using the beforeunload event and then making the handler return null. This executes the wanted code without a confirmation box popping-up. It goes something like this:
window.onbeforeunload = closingCode;
function closingCode(){
// do something...
return null;
}
Sometimes you may want to let the server know that the user is leaving the page. This is useful, for example, to clean up unsaved images stored temporarily on the server, to mark that user as "offline", or to log when they are done their session.
Historically, you would send an AJAX request in the beforeunload function, however this has two problems. If you send an asynchronous request, there is no guarantee that the request would be executed correctly. If you send a synchronous request, it is more reliable, but the browser would hang until the request has finished. If this is a slow request, this would be a huge inconvenience to the user.
Later came navigator.sendBeacon(). By using the sendBeacon() method, the data is transmitted asynchronously to the web server when the User Agent has an opportunity to do so, without delaying the unload or affecting the performance of the next navigation. This solves all of the problems with submission of analytics data: the data is sent reliably, it's sent asynchronously, and it doesn't impact the loading of the next page.
Unless you are targeting only desktop users, sendBeacon() should not be used with unload or beforeunload since these do not reliably fire on mobile devices. Instead you can listen to the visibilitychange event. This event will fire every time your page is visible and the user switches tabs, switches apps, goes to the home screen, answers a phone call, navigates away from the page, closes the tab, refreshes, etc.
Here is an example of its usage:
document.addEventListener('visibilitychange', function() {
if (document.visibilityState == 'hidden') {
navigator.sendBeacon("/log.php", analyticsData);
}
});
When the user returns to the page, document.visibilityState will change to 'visible', so you can also handle that event as well.
sendBeacon() is supported in:
Edge 14
Firefox 31
Chrome 39
Safari 11.1
Opera 26
iOS Safari 11.4
It is NOT currently supported in:
Internet Explorer
Opera Mini
Here is a polyfill for sendBeacon() in case you need to add support for unsupported browsers. If the method is not available in the browser, it will send a synchronous AJAX request instead.
Update:
It might be worth mentioning that sendBeacon() only sends POST requests. If you need to send a request using any other method, an alternative would be to use the fetch API with the keepalive flag set to true, which causes it to behave the same way as sendBeacon(). Browser support for the fetch API is about the same.
fetch(url, {
method: ...,
body: ...,
headers: ...,
credentials: 'include',
mode: 'no-cors',
keepalive: true,
})
jQuery version:
$(window).unload(function(){
// Do Something
});
Update: jQuery 3:
$(window).on("unload", function(e) {
// Do Something
});
Thanks Garrett
The documentation here encourages listening to the onbeforeunload event and/or adding an event listener on window.
window.addEventListener('beforeunload', function(event) {
//do something here
}, false);
You can also just populate the .onunload or .onbeforeunload properties of window with a function or a function reference.
Though behaviour is not standardized across browsers, the function may return a value that the browser will display when confirming whether to leave the page.
You can use window.onbeforeunload.
window.onbeforeunload = confirmExit;
function confirmExit(){
alert("confirm exit is being called");
return false;
}
The event is called beforeunload, so you can assign a function to window.onbeforeunload.
Is there a way to execute the code quietly? (no popup)
I have used this successfully, where other methods (eg returning null or false) had issues. Tested on ie, Edge, Chrome, Opera.
window.addEventListener('beforeunload', function (e) {
// the absence of a returnValue property on the event will guarantee the browser unload happens
delete e['returnValue'];
// my code that silently runs goes here
});
The above code is pasted directly from Mozilla.org's onbeforeunload doc
Update: This doesn't appear to work on IOS Safari :( So not a total solution, but maybe it still helps someone.