jQuery, onBeforeUnload and ASP.Net form - javascript

I have the following solution for stopping the users from accidentally leaving my registration page:
var warning = true;
function CheckExit() {
if (warning) {
return "Changes done. Remember to save, blah blah.";
}
}
window.onbeforeunload = CheckExit;
addToPostBack = function (func) {
var old__doPostBack = __doPostBack;
if (typeof __doPostBack != 'function') {
__doPostBack = func;
} else {
__doPostBack = function (t, a) {
if (func(t, a)) old__doPostBack(t, a);
}
}
};
$(document).ready(function () {
$('#aspnetForm').submit(function () {
warning = false;
return true;
});
addToPostBack(function (t, a) {
warning = false;
return true;
});
});
Most of this code is from different questions here on StackOverflow, and works just fine on my local debugging page; all ASP.Net controls (linkbuttons, buttons) can be clicked without a warning, but as soon as the user tries to close the window or navigate away, the warning is displayed.
However, when deployed to my server, the warning pops up when I click ASP.Net controls too (and I really do not want to warn the user that his changes isn't saved when he clicks the "Save" button). Now, there is a difference between my local debugging page and the server: the server uses a different MasterPage with some ads in it, but after debugging with Firebug (see next paragraph), I can't see how that should make a difference.
I have tried running different parts of the Javascript code by using Firebug to confirm that everything is loaded correctly (my first guess was that the section containing $('#aspnetForm') wasn't being loaded, since this seems to be the difference), but there is no improvement at all. The warning still pops up on every click of a link or a button.
My main problem is, I think, that I do not fully understand what the addToPostBack function does, and as such, I cannot properly debug it.
Is there anybody here who has any idea what might be wrong?

It's a guess, but you don't have the conventional anti-conflict device which goes
(function ($) { code here })(jQuery);
so something might be conflicting with jQuery's definition of '$' which would stop the execution of the exception your code makes when someone is posting back.

I agree with James. Most of the time such type of conflict occurs. I will suggest with noConflict().
Happy Coding.

Related

How to extract target hostname during onbeforeunload event

I'd like to warn the user when he/she tries to navigate away from my webapp when his/her project is unsaved. Currently I don't care about edit boxes which are currently under edit. I know the project's dirty state from the session.
I quickly realized that if I set a function for the window.onbeforeunload, it'll disturb the user even if he/sh navigates to another page within my webapp. In such case no disturbance needed, the session will be still alive.
I tried a solution derived from Fire onbeforeunload only when window is closed (includes working example)
window.onbeforeunload = function (e) {
var targetHost = new URL(e.target.URL).hostname;
if (targetHost != window.location.host)
return "Project is unsaved!!!";
else
return null;
};
The new URL(e.target.URL).hostname results in (at least on IE11):
JavaScript runtime error: Object doesn't support this action
And mysteriously I can't find anything about no new URL(e.target.URL).hostname by any search.
But at the same time I hope this is not impossible, I cannot believe others didn't experience this.
There are two problems in your script:
window.onbeforeunload = function (e) {
var targetHost = new URL(e.target.URL).hostname;
if (targetHost != window.location.host) {
return "Project is unsaved!!!";
else
return null;
};
The first is that you did not close your if. The second is that e.target.URL is apparently not supported by IE. You need to have an A and a B plan.
A plan: Applies to the case when e.target.URL exists. In this case, you handle the case as you initially implemented, but with the syntax fix mentioned above.
B plan: Applies to the case when e.target.URL does not exist. For this case, you should assume that the user leaves the site. You can improve the approach by adding knowledge when the user uses your control to navigate, for instance, you know that a given anchor will stay on the site. In this case, you can define a click event and set a boolean value to true (and the default value of that boolean should be false...), so that later your onbeforeunload event will know that your user stayed on the site even if he or she uses IE.
So you need a logic like this:
var targetHost = !!e.target.URL ? (new URL(e.target.URL).hostname) : ((myFlag) ? (window.location.hostname) : ("elsewhere"));

Ajax .load() won't work when triggered initially

So I have a simple tab system which I handle with the .load function to load the desired content. The problem is that the page itself which contains this tab system is a ajax loaded content. And for some reason the initial call of the tab function to display the initial tab content won't work. But after manually choosing a tab, the load function loads the content properly.
her some code to look at:
The tab handler:
function loadTab(tab) {
$(".tab_a:eq("+otab+")").removeClass("tab_slc");
$('#tab_content').hide();
$('#tab_content').load("include/tab_downloadVersions.html .tab:eq("+tab+")");
$(".tab_a:eq("+tab+")").addClass("tab_slc");
$('#tab_content').fadeIn(function() {});
otab = tab;
}
at the end I call loadTab(tab); and the thing should be initialized. but for some reason the content remains empty. As soon as you manually click on a tab (I have an on click function which calls loadTab(tab) everything starts working)
Because the code by itself works, I think the problem is caused by the other script which handles the page itself. It is also a .load function which loads the page, which loads this tab system.
So do multiple .loads don't like each other? and if so, what can I change?
Thanks in advance ;)
EDIT: I could't post the entire code for some reason, but if you go here you can see the site in action with all the scripts:
n.ethz.ch/student/lukal/paint.net
The tab system is on the download page.
EDIT:-----------------------------------------------------------------------------------------------------------------------------
Big Update
So this is still the same issue but with a slight twist: I did what was recommended in the comments and put my secondary .load() call inside the success call of the first one.
$("#content").load("pages/contact #contentInside", function() {
$("#OtherContent").load("include/info #OtherContentInside");
});
So this works.
But now I had the great idea to make a giant load function. It is a slightly better function than just the plain load, cause it does some fading and stuff. But now I have the same problem, but even more complicated. I created the load function as a "plugin" so the function itself is in a different script file and therefore I can't access the inside of the success function. I solved this problem with a return $.ajax(); and a .done() call. The problem here is that there is some rare case where it just skips the secondary load function. So I am searching for a guaranteed way of controlling the order of the .load calls. Any idea?
The mock-up website is up to date with the new scripts if you wish to take a look. And people were complaining about potential virus spread from my link. For some reason I can't post long code snippets so the site is the best source I got to show everything. If you know a more trustworthy way to share my code please let me know.
We cannot see the rest of your code to tell where the initial call is being invoked from. A set up like the following should work:
$(function() {
var tab = 0;
loadTab( tab );
});
function loadTab(tab) {
//WHAT IS otab???
$(".tab_a:eq("+otab+")").removeClass("tab_slc"); //<<<==== otab
$('#tab_content').hide();
$('#tab_content').load("include/tab_downloadVersions.html .tab:eq("+tab+")");
$(".tab_a:eq("+tab+")").addClass("tab_slc");
$('#tab_content').fadeIn(function() {});
otab = tab;
}
Update
The reason it does not work initial is because otab is not defined the first time the function is called. You have initialized otab at the end of the function but you are using it at the beginning of the function.
UPDATE 2
I have had a chance to look at your code and I just found out what the issues are:
You do not have DOM ready
You are not calling the function on page load.
The following version of your code should work -- try not to use global variable as you're doing with otab. Since you're loading this script at the end of the page (an you are using event delegation) you may get away with DOM ready. Adding .trigger('click') or click() as indicated below should resolve the issue.
//Tab-loader
//Haeri Studios
var tab = 0;
var otab = tab;
var counter = 0;
//click detect
$(document).on('click', '.tab_a', function() {
tab = counter == 0 ? tab : ($(this).attr('id'));
loadTab(tab);
counter++;
return false;
})
.trigger('click'); //<<<<<===== This will call the function when the page loads
//Tab setup
function loadTab(tab) {
//Content Setup
$(".tab_a:eq("+otab+")").removeClass("tab_slc");
$('#tab_content').hide();
$('#tab_content').load("include/tab_downloadVersions.html .tab:eq("+tab+")");
$(".tab_a:eq("+tab+")").addClass("tab_slc");
$('#tab_content').fadeIn(function() {});
otab = tab;
}
//Initialize << WHAT ARE YOUR INTENTIONS HERE .. DO YOU REALLY NEED THIS PIECE?
$.ajax({success: function() {
loadTab(tab);
}});
A partial answer to this problem was to call the loadTab function inside the success call of the page load function, like charlietfl pointed out. But the problem is that there is no need to call the tabloader every time a new page gets called. So I would rather not have a rare call in every page setup function.
I am a bit disappointed by the system on stackoverflow. It seems like if you have not a high reputation level, no one gives a "S" about your questions. Well but at least some input was give, for which I am very thankful.
So by digging deeper into google I found out that the callback can be manually placed in the function where ever you like.
so if we have a function:
foo(lol, function() {
//This after
});
this does stuff after foo() is done. But what if we have another function inside foo() which we also need to wait for:
function foo(lol) {
bar(troll, function() {
//This first
});
}
The bar function is not relevant to the success call of foo. This causes the unpredictable outcome of calls.
The trick is to control when the success function of foo gets called.
If we add a parameter(callback) inside foo and call this "parameter" (callback();) inside the success call of bar, we can make sure the order is guaranteed.
And that's it:
function foo(lol, callback) {
bar(troll, function() {
//This first
callback(); //<-This callback placement defines when it should be triggered
});
}
foo(lol, function() {
//This after
});
We get:
//this first
//this after

Checking for unsaved changes when switching views in backbone.js

I am new to Javascript and backbone.js, so hopefully I am missing something simple here. I am experimenting with some sample code I found which is supposed to check for unsaved changes before allowing a user to navigate away to another page. I have created a JSfiddle here:
http://jsfiddle.net/U43T5/4/
The code subscribes to the hashchange event like this:
$(window).on("hashchange", router.hashChange);
And the router.hashChange function checks a "dirty" flag to determine whether or not to allow the navigation, like this:
hashChange: function (evt) {
if (this.cancelNavigate) { // cancel out if just reverting the URL
evt.stopImmediatePropagation();
this.cancelNavigate = false;
return;
}
if (this.view && this.view.dirty) {
var dialog = confirm("You have unsaved changes. To stay on the page, press cancel. To discard changes and leave the page, press OK");
if (dialog == true) return;
else {
evt.stopImmediatePropagation();
this.cancelNavigate = true;
window.location.href = evt.originalEvent.oldURL;
}
}
},
The problem is that the code is not working because this.view is undefined, so the 2nd if block is never entered.
I would like the sample program to always ask for confirmation before navigating away from the page (in my sample program, I have set this.view.dirty to always be true, which is why it should always ask for confirmation). Or if there is a better approach, I am open to alternatives.
The main issue is the this context in the methods , this corresponds to the Window Object and not the Router. So it always remains undefined as you are defining view on the router. Declare a initialize method which binds the context inside the methods to router.
initialize: function() {
_.bindAll(this, 'loadView', 'hashChange');
},
Check Fiddle
I spent a lot of time to make at least something decent.
I ended up writing a wrapper for Backbone function:
var ignore = false;
Backbone.history.checkUrl = function() {
if (ignore) {
ignore = false;
return;
}
app.dirtyModelHandler.confirm(this, function () {
Backbone.History.prototype.checkUrl.call(Backbone.history);
},
function() {
ignore = true;
window.history.forward();
});
};
app.dirtyModelHandler.confirm is a function which shows confirmation (Ok, Cancel) view and takes success and cancel functions as arguments.

Return parent function from child function on click

How can I return a parent function from a child function on click? Here's an example code:
function returnFunction() {
var output = false;
$('a').click(function() {
output = true;
});
return output;
}
var result = returnFunction();
The result will always be false since the click hasn't happened at the time the code is being run. How could I make this work though?
My intention is to call pop-up dialogs, and I'd like to have all the logic inside one function that can easily be loaded - including the click events of a Confirm dialog box.
Elsewhere in scripts I'd be calling it this way for example:
// Menu click triggers the dialog
$('a').click(function(e) {
// The function displays the dialog and returns the click events of the dialog
var result = returnFunction();
// If result was false, we'll prevent the menu access, for example
if (!result) {
e.preventDefault();
}
});
I'm aware of the jQuery UI dialog plugin. But I'd like to achieve this without it for now.
Thanks.
An over-simplification of it is:
Everything stops (including scrolling and clicking on hyperlinks) while executing javascript. This means you cannot "pause" the script until someone clicks on a link.
The typical way of solving this is a callback function:
function my_callback(some, arguments) {
// you can do whatever in here: an ajax load, set a global variable, change some of the page, ...
console.log(some, arguments);
alert(some + " " + arguments);
}
function returnFunction(callback, param) {
var output = false;
$('a').click(function() {
callback(param, "world");
});
}
returnFunction(my_callback, "hello");
demo at http://jsfiddle.net/UnBj5/
EDIT:
I did mention global variables because they are an option, but they are typically bad style. Try to use other means if possible.
If you want more help with it, provide more details of what you are trying to do.
Try using parameters instead. Send a parameter to a function that shows your alert boxes, show a different pop-up alert depending on the parameter, what you are trying to do won't work because its basically a chicken-egg problem.

To execute Flex cleanup function when browser is closed by user

I have a Flex client application. I need a clean up function to run in Flex when the user closes the browser. I found the following solution on the net, but it only works half-way for me. How could I fix it? Thanks in advance for any responses!
Symptoms
CustomEvent triggered, but not executed. >> EventHandler for CustomEvent.SEND_EVENTS is defined by a Mate EventMap. All the handler does is to call an HTTPServiceInvoker. In debug console, I'm able to see the handler and HTTPServiceInvoker being triggered, but neither the resultHandlers nor the faultHandlers were called. I know this event handler has no problem because when I dispatch the same CustomEvent.SEND_EVENTS in a button click handler, it behaves exactly as I expected)
Browser seems to wait for cleanUp function to complete before it closes. (all traces were printed before browser closes down)
Code
I added the following into the index.template.html
window.onbeforeunload = clean_up;
function clean_up()
{
var flex = document.${application} || window.${application};
flex.cleanUp();
}
And used the following in the application MXML file
import flash.external.ExternalInterface;
public function init():void {
ExternalInterface.addCallback("cleanUp",cleanUp);
}
public function cleanUp():void {
var newEvent:CustomEvent = new CustomEvent(CustomEvent.SEND_EVENTS);
newEvent.requestObj = myFormModel;
dispatchEvent(newEvent);
// for testing purposes
// to see whether the browser waits for Flex cleanup to finish before closing down
var i:int;
for (i=0; i<10000; i++){
trace(i);
}
}
My Setup
FlexBuilder 3
Mate MVC Framework (Mate_08_9.swc)
FlashPlayer 10
Unfortunately, there is no solid way of doing such clean up functions that execute asynchronously. The result/fault events of the HTTPService occur asynchronously after the cleanUp method is returned. The browser waits only till the onbeforeunload function (the js clean_up function) returns. Unless you call event.preventDefault() from that function, the page will be closed. Note that calling preventDefault() will result in an ok/cancel popup asking:
Are you sure you want to navigate away from this page?
Press OK to continue, or Cancel to stay on the current page.
If the user selects OK, the browser will be closed nevertheless. You can use the event.returnValue property to add a custom message to the popop.
//tested only in Firefox
window.addEventListener("beforeunload", onUnload, false);
function onUnload(e)
{
e.returnValue = "Some text that you want inserted between " +
"'Are you sure' and 'Press OK' lines";
e.preventDefault();
}
You'll never be able to reliably detect the browser code 100% of the time. If you really need to run actions then the safest course of action is to have clients send "i'm still alive" messages to the server. The server needs to track time by client and when a client doesn't send a message within the specified amount of time (with some wiggle room), then run clean-up activities.
The longer you make the time the better, it depends on how time-critical the clean-up is. If you can get away with waiting 5 minutes that's great, otherwise look at 1 minute or 30 seconds or whatever is required for your app.
An alternate way to clean up the session on client side is to use JavaScript and external.interface class in as3. Here is sample code:
JavaScript:
function cleanUp()
{
var process;
var swfID="customRightClick";
if(navigator.appName.indexOf("Microsoft") != -1){
process = window[swfID];
}else
{
process = document[swfID];
}
process.cleanUp();
}
and in the as3 class where the clean up function is defined use this:
import flash.external.ExternalInterface;
if (ExternalInterface.available)
{
ExternalInterface.addCallback("cleanUp", cleanUp);
}
function cleanUp():void {// your code }

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