How to capture when a user is leaving ASP.Net page unexpectedly - javascript

I need to prompt a user when they are leaving my ASP.Net page unexpectedly with a message to ask if they are sure they want to leave. A post back or when the save button is clicked should not fire the warning. There are a bunch of articles covering this but I am brand new to this and appear to have got my wires crossed.
The recommended way appears to be to use the window.onbeforeunload event but behaves unexpectedly for me. This is fired when the page loads as opposed to when the page unloads.
<script language="JavaScript" type="text/javascript">
window.onbeforeunload = confirmExit;
function confirmExit() {
return "You have attempted to leave this page. If you have made any changes to the fields without clicking the Save button, your changes will be lost. Are you sure you want to exit this page?";
}
</script>
If I use the JQuery implementation it fires when the page unloads but the problem is it fires before the code behind is executed. So I cannot set a variable on the client saying don’t fire the event this time as it is a post back or a Save.
$(window).bind('beforeunload', function () {
return 'Are you sure you want to leave?';
});
Can anyone point me in the correct direction as I know I am making basic mistakes/miss-understanding?
Edit:
So I am nearly there:
var prompt = true;
$('a').live('click', function () {
//if click does not require a prompt set to false
prompt = false;
});
$(window).bind("beforeunload", function () {
if (prompt) {
//reset our prompt variable
prompt = false;
//prompt
return true;
}
})
Except the problem is in the above code I need to be able to differentiate between the clicks but I haven't been able to figure that out yet i.e. I am missing a condition here "//if click does not require a prompt set to false".
Any ideas?
Thanks,
Michael

You can try using this:
$(window).unload(function(){
alert('Message');
});

In case people are interested this is the roundabout solution to my problem. How to tell if a page unload in ASP is a PostBack

Related

Prevent user to leave page without the confirmation

I have found on StackOverflow this script that handles the issue when a user wants to leave the page, to ask him before doing it.
ISSUE
It is working fine (even though there is probably a much better solution) but I have realized that it is causing one "bug". When a user sends data from the form and the script asks him does he want to leave the page (because of the redirect) it still sends data. So, even if the user clicks on "Cancel" it will still proceed to the store() method and if the user adds something more and sends again the data I get duplicates. Is there a way to include "stop propagation" in this script?
CODE
window.onbeforeunload = function () {
return 'Are you sure you want to close this website?';
};
Additional question
Since this script is running with the Laravel Livewire, every time I click on any button related to the livewire (which won't redirect the user to the other page) script prompts the popup to ask if the user is sure he wants to leave the page. Is there any workaround (if you need some other code, write a comment because I am not sure which part could help you at all :) ) for this issue?
Try this:
<script>
window.onbeforeunload = function (e) {
e = e || window.event;
// For IE and Firefox prior to version 4
if (e) {
e.returnValue = 'Sure?';
}
// For Safari
return 'Sure?';
};
</script>
Here is a working jsFiddle

How can I warn user on back button click?

www.example.com/templates/create-template
I want to warn users if they leave create-template page. I mean whether they go to another page or to templates.
I use this code to warn users on a page reload and route changes should the form be dirty.
function preventPageReload() {
var warningMessage = 'Changes you made may not be saved';
if (ctrl.templateForm.$dirty && !confirm(warningMessage)) {
return false
}
}
$transitions.onStart({}, preventPageReload);
window.onbeforeunload = preventPageReload
It works as expected on a page reload and route changes if it is done by clicking on the menu or if you manually change it. However, when I click the back button, it does not fire the warning. only it does if I click the back button for the second time, reload the page, or change route manually.
I am using ui-router. When you click back button, you go from app.templates.create-template state to app.templates state.
How to warn if they press Back button?
First of all, you are using it wrong:
from https://developer.mozilla.org/en-US/docs/Web/API/WindowEventHandlers/onbeforeunload:
Note: To combat unwanted pop-ups, some browsers don't display prompts
created in beforeunload event handlers unless the page has been interacted
with; some don't display them at all. For a list of specific browsers, see the
Browser_compatibility section.
and
window.onbeforeunload = funcRef
funcRef is a reference to a function or a function expression.
The function should assign a string value to the returnValue property of the Event object and return the same string.
You cannot open any dialogs in onbeforeunload.
Because you don't need a confirm dialog with onbeforeunload. The browser will do that for you if the function returns a value other than null or undefined when you try to leave the page.
Now, as long as you are on the same page, onbeforeunload will not fire because technically you are still on the same page. In that case, you will need some function that fires before the state change where you can put your confirm dialog.
How you do that depends on the router that you are using. I am using ui-router in my current project and I have that check in the uiCanExit function.
Edit:
You can keep your preventPageReload for state changes in angular. But you need a different function for when the user enters a new address or tries to leave the page via link etc.
Example:
window.onbeforeunload = function(e) {
if (ctrl.templateForm.$dirty) {
// note that most broswer will not display this message, but a builtin one instead
var message = 'You have unsaved changes. Do you really want to leave the site?';
e.returnValue = message;
return message;
}
}
However, you can use this as below:(using $transitions)
$transitions.onBefore({}, function(transition) {
return confirm("Are you sure you want to leave this page?");
});
Use $transitions.onBefore insteadof $transitions.onStart.
Hope this may help you. I haven't tested the solutions. This one also can help you.

How to logout during onbeforeunload/onunload using Javascript

<script type="text/javascript">
window.onbeforeunload=before;
window.onunload=after;
function before(evt)
{
var message="If you continue, your session will be logged out!";
if(typeof evt=="undefined"){
evt=window.event;
}
if(evt){
evt.returnValue=message;
}
}
function after()
{
var flex=document.${application}||window.${application};
flex.unloadMethod(); //calls the flex class containing the "unloadMethod()" which
//calls the logout.jsp that does the actually dropping of credentials
}
</script>
So this is my thought:
When the user clicks back, refresh, or closes the window, the standard onbeforeunload pop-up box will appear along with the text located in my message variable. Then, if the user hits Cancel, the onunload event won't be executed and the user will stay on the current page. But if the user hits Okay, then the onunload event should fire off, which then executes my logoff classes.
This is what's happening:
The pop-up appears when needed and the Cancel button also works. But if the user clicks Okay, it seems like the onunload event fires off too quickly for my logoff classes to execute, because it never logs them off.
I know that my logout classes work because if I just call my flex.unloadMethod in the onbeforeunload, it logs them off.
I've researched this for a week now and it seems that I'm close but I'm putting something in the wrong place. If you have any examples or advice, it would be appreciated.
So, I've figured out some issues with my question with the help of Sunil D. The onunload event fires too quickly for my event to be triggered, so I've decided not to include a warning message, but just log the user off all together using the onbeforeunload event:
<script type="text/javascript">
window.onbeforeunload=before;
window.onunload=after;
function before(evt)
{
var flex=document.${application}||window.${application};
flex.unloadMethod(); //calls the flex class containing the "unloadMethod()" which
//calls the logout.jsp that does the actually dropping of credentials
}
function after(evt)
{
}
</script>

Javascript unload page condition

I am using the following code to prompt the user that if he left the page he can't come back. Things happened that i want to redirect the page using setTimeout function after a specific time. I want to disable checking for user leaving the page when the automatic redirection starts.
<script language="javascript" type="text/javascript">
needToConfirm = true;
window.onbeforeunload = askConfirm;
function askConfirm(){
if (needToConfirm){
return "Please note that you might not be able to come back and watch the movie again.";
}
}
</script>
Unset onbeforeunload in the function called by setTimeout before you redirect the user:
window.onbeforeunload = null;

Yes/No box in Javascript like this one here in StackOverflow?

I want to know how can I display a confirmation box when the users try to get out of the page, like this one here in StackOverflow when you try to close the "Ask Question" page.
Thanks you in advance.
Actually, all that is necessary is this:
window.onbeforeunload = function(){ return "You should save your stuff."; }
This is also kind of a dupe of this: How to show the "Are you sure you want to navigate away from this page?" when changes committed?
In javascript, attach a function to window.onbeforeunload, like so:
window.unbeforeunload = function (e)
{
// return (prompt ('Are you sure you want to exit?'));
// EDIT: Amended version below:
var e = e || window.event;
if (e) e.returnValue = 'Your exit prompt';
return 'Your exit prompt';
}
EDIT:
As the comments below indicate, I had misunderstood the working of the event. It should now work as intended.
Ref: window.onbeforeunload (MDC)
probably a dupe: How do you prevent a webpage from navigating away in JavaScript?, but you can do this by adding an delegate to the window.onbeforeunload event
<script type="text/javascript">
window.onbeforeunload = function() {
//will show a dialog asking the user if
//they want to navigate away from the current page
// ok will cause the navigation to continue,
// cancel will cause the user to remain on the current page
return "Use this text to direct the user to take action.";
}
</script>
Update: doh! updated code to do what the OP really wanted :D
You want to catch the onbeforeunload event of window. Then if you return a string, the browser will display your message in a prompt. Here's an article with sample code.
You can use the window.onbeforeunload event to catch this. If there is any value inside the textarea then an alert message is shown.
That's browser based.
As long as you implement <form> tag, and you type in something in the form, and in Google Chrome, it will prompt you that message.

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