cursor not stopping until button click completes in window.onbeforeunload? - javascript

I have below javascript code for window.onbeforeunload. I am calling code behind button click method when pressed browser back button.
Now the problem is cursor is not stopping until $("#buttonclientid").click() completes. Just calling the method and moving to next statement. How to hold or stop cursor until $("#buttonclientid").click() complete and then move to next step?
var form_has_been_modified = 0;
$(function () {
$("input").keyup(function () {
form_has_been_modified = 1;
})
window.onbeforeunload = function (e) {
if (!form_has_been_modified) {
return;
}
doYouWantTo();
}
});
function doYouWantTo(){
doIt=confirm('Do you want to save the data before leave the page?');
if (doIt) {
var returnbutton;
//cursor should stop here until click function completes.
returnbutton = $("#buttonclientid").click();
}
else{
}
}


I believe your problem lies in the fact that your doYouWantTo function does not return a value to be passed back into onbeforeunload so it is leaving the page while also running the function, rather than waiting until it completes.
Your best action here would be something like:
return doYouWantTo()
....
if(doIt) {
$('#buttonclientid').click(function() { // unsure if you can attach callback to click but idea is same
return true;
});
} else {
return true;
}


When binding an event handler to the onbeforeunload event, it should return one of two things:
if you want a confirm to show, your handler should return a string
if you don't want a confirm to show (skip the handler), return undefined (or don't return at all, same effect)
That being said, your code should look something like this:
var form_has_been_modified = false;
$("input").keyup(function () {
form_has_been_modified = true; // use a boolean :P
});
window.onbeforeunload = function (e) {
if (form_has_been_modified) {
return 'Do you want to save the data before leave the page?';
} else {
return undefined; // this can be omitted if you prefer
}
};
The only way to tell what a user clicked on the system dialog is to use setTimeout. See this question for details on that subject.

Related

How to execute function while handle 2 events at same time?

I have some code that wants to be executed while the user resizing an element and scrolling the window at the same time tow events must occur at the same time to execute the function something like the following but I want to merge them to be like one custom event?
this.on("resize", function() {
$(window).scroll(function() {
figure.setHeight(_this.getHeight());
_this.setHeight(figure.getHeight());
});
});

Explanation : I have used a flag here, initially set to false. As it is given that both events will be happening, we can make a check in one function is the other is happening or not and execute the desired function.
First of all click the button. A console will be generated, that clicked. Now flag is set to true. But myFunction() is not eecuted, coz it will fire only when keydown will take place. In case key is pressed, flag won't be true, and hence myFunction() will not be executed. Now that you know that, button was clicked, so it has the focus. On pressing enter key, it will do perform click and keydown at same time. And myFunction() will get executed. When it gets executed, set flag to false. :)
var flag = false;
$(document).on("keydown", function() {
flag = true;
console.log("key pressed");
});
$('button').click(function() {
console.log("clicked");
if (flag) {
myFunction();
}
});
function myFunction() {
alert("Both at same time");
flag = false;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<button>Click me</button>

From my understanding the resize event is triggered first, and then if the user also scrolls your custom function should be called
let resizeTriggered = false
const myResizeFunc = (event) => {
resizeTriggered = true
}
const myScrollFunc = (event) => {
if (resizeTriggered) {
myCustomFunction()
}
}
const myCustomFunction = () => {
console.log('both are happening')
}
$('#textArea').mousedown(myResizeFunc)
$(window).scroll(myScrollFunc)
div.large {
height:1000px;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<textarea id="textArea"></textarea>
<div class="large">
</div>

How to temporary disable the click function when it is executing?

$("#prevPage").live("click",function(e) {
.................
});
For example, when the user have already clicked on the prevPage, the statement inside it is running, if the user click on it instantly , it will trigger again. However, I would like the click event trigger only after all the statement inside it have finish execution, How to achieve that?

How about this or something similar:
<script type="text/javascript">
// disable command while function is being executed.
var sample = {
isExecuting : 0,
doWork : function (e) {
if (sample.isExecuting === 1) return;
sample.isExecuting = 1;
// do work -- whatever you please
sample.isExecuting = 0; // say: I'm done!
}
};
// live or bind
$("#prevPage").bind("click",function(e) {
sample.doWork(e);
});
</script>
simple 'shield' to block a multiple-call scenario.

Then set a flag on the element to check if it's clickable or not.
$("#prevPage").on("click",function(e) {
e.preventDefault();
//get the clickable attribute
//if it's not existent, its undefined hence "false"
var unclickable = this.unclickable;
//if it's not unclickable (it's clickable)
if(!unclickable){
//make the flag unclickable
this.unclickable = true;
//do stuff
//reset it back the way it was after operations
this.unclickable = false;
}
});

Set a variable that your event triggered
var prevPageEventTriggered = false ;
and set it to ture when event triggered
prevPageEventTriggered = true;
and then add condition for this in click event handler function
$("#prevPage").live("click",function(e) {
if ( prevPageEventTriggered ) {
return false;
}
// your code goes here
// ....
});
if it have finish execution, you can set it to false . hope this will helps

use the unbind function of jquery
$("#prevPage").unbind("click");
after your task finished
$("#prevPage").bind("click",function(){....your code here....});

unbind() will do the work for you.
An alternate could be like using detach(). When your process is executing detach the button and when your process finsihes executing, use reattach() to get the button back.
What I will suggest is use unbind().

Why is my .blur() code only working on second blur?

I have an input, when the user enters something, my script sends the info over to a php script, which returns whether or not the entered text can be used.
If the text can not be used, it disables the submit button and adds a class to the reult text.
The problem have is strange, the ajax works, the result is returned, but the button disabling and adding of the class doesn't happen unless you focus and blur the input a second time.
Here is my code:
$('#alias').blur(function() {
if ($('#alias').val()) {
var aliascheck = $('#alias').val();
$(".aliascheck").load('checkalias.php?alias='+aliascheck);
var result = $('.aliascheck').text();
if (result.indexOf("Taken") != -1) {
$('#shorten').attr("disabled","disabled");
$('.aliascheck').addClass('error');
} else {
$('#shorten').removeAttr("disabled");
$('.aliascheck').removeClass('error');
}
}
});
The code is live here: http://markhenderson.ws/dev/tmtmu/
To replicate the "taken" event, enter "taken" as the alias. Any thing else will return available.
Does anyone know why this is happening?
Thanks

You need to put the code after the .load call into a callback function of the async call.
Something like:
$('#alias').blur(function() {
if ($('#alias').val()) {
var aliascheck = $('#alias').val();
$(".aliascheck").load('checkalias.php?alias='+aliascheck, function() {
var result = $('.aliascheck').text();
if (result.indexOf("Taken") != -1) {
$('#shorten').attr("disabled","disabled");
$('.aliascheck').addClass('error');
} else {
$('#shorten').removeAttr("disabled");
$('.aliascheck').removeClass('error');
}
});
}
});

Prevent click event from firing when dblclick event fires

I'm handling both the click and dblclick event on a DOM element. Each one carries out a different command, but I find that when double clicking on the element, in addition to firing the double click event, the click event is also fired twice. What is the best approach for preventing this behavior?

In case anyone else stumbles on this (as I did) looking for an answer, the absolute best solution that I could come up with is the following:
$node.on('click',function(e){
if(e.originalEvent.detail > 1){
return;
/* if you are returning a value from this
function then return false or cancel
the event some other way */
}
});
Done. If there is more than one click back to back, the second, third,etc. will not fire. I definitely prefer this to using any sort of timers.
I got myself pointed in this direction by reading this.
Incidentally: I was first researching this problem because I accidentally double clicked a paginated link, and the event fired and finished twice before the callback could happen.
Before coming up with the code above, I had
if e.originalEvent.detail === 2 //return
however, I was able to click on the link 3 times (a triple click), and though the second click didn't fire, the third did

In a comment, you said,
I delay the click handler by 300 ms (a noticeable and annoying delay) and even ...
So it sounds like what you want is that when you click then the DOM should geneate a click event immediately, except not if the click is the first click of a double-click.
To implement this feature, when you click, the DOM would need to be able to predict whether this is the final click or whether it's the first of a double-click (however I don't think is possible in general for the DOM to predict whether the user is about to click again).
What are the two distinct actions which you're trying to take on click and double-click? IMO, in a normal application you might want both events: e.g. single-click to focus on an element and then double-click to activate it.
When you must separate the events, some applications use something other than double-click: for example, they use right-click, or control-click.

You can use UIEvent.detail if you want to detect how many times the element was clicked and fire events based on that.
A simple example:
element.addEventListener("click", function (e) {
if (e.detail === 1) {
// do something if the element was clicked once.
} else if (e.detail === 2) {
// do something else if the element was clicked twice
}
});

In this case, it is best to delay the execution of the single click event slightly. Have your double click handler set a variable that the single click event will check. If that variable has a particular value, could be boolDoubleClick == true, then don't fire/handle the single click.

Thanks to all the other answers here as the combination of them seems to provide a reasonable solution for me when the interaction requires both, but mutually exclusive:
var pendingClick = 0;
function xorClick(e) {
// kill any pending single clicks
if (pendingClick) {
clearTimeout(pendingClick);
pendingClick = 0;
}
switch (e.detail) {
case 1:
pendingClick = setTimeout(function() {
console.log('single click action here');
}, 500);// should match OS multi-click speed
break;
case 2:
console.log('double click action here');
break;
default:
console.log('higher multi-click actions can be added as needed');
break;
}
}
myElem.addEventListener('click', xorClick, false);
Update: I added a generalized version of this approach along with a click polyfill for touch devices to this Github repo with examples:
https://github.com/mckamey/doubleTap.js

AFAIK DOM Level 2 Events makes no specification for double-click.
It doesn't work for me on IE7 (there's a shock), but FF and Opera have no problem managing the spec, where I can attach all actions to the click event, but for double-click just wait till the "detail" attribute of the event object is 2. From the docs: "If multiple clicks occur at the same screen location, the sequence repeats with the detail attribute incrementing with each repetition."

Here is what I did to distinguish within a module
node.on('click', function(e) {
//Prepare for double click, continue to clickHandler doesn't come soon enough
console.log("cleared timeout in click",_this.clickTimeout);
clearTimeout(_this.clickTimeout);
_this.clickTimeout = setTimeout(function(){
console.log("handling click");
_this.onClick(e);
},200);
console.log(_this.clickTimeout);
});
node.on('dblclick', function (e) {
console.log("cleared timeout in dblclick",_this.clickTimeout);
clearTimeout(_this.clickTimeout);
// Rest of the handler function

I use this solution for my project to prevent click event action, if I had dblclick event that should do different thing.
Note: this solution is just for click and dblclick and not any other thing like tripleclick or etc.
To see proper time between click and double click see this
sorry for my bad English.
I hope it helps :)
var button, isDblclick, timeoutTiming;
var clickTimeout, dblclickTimeout;
//-----
button = $('#button');
isDblclick = false;
/*
the proper time between click and dblclick is not standardized,
and is cutsomizable by user apparently (but this is windows standard I guess!)
*/
timeoutTiming = 500;
//-----
button.on('dblclick', function () {
isDblclick = true;
clearTimeout(dblclickTimeout);
dblclickTimeout = setTimeout(function () {
isDblclick = false;
}, timeoutTiming);
//-----
// here goes your dblclick codes
console.log('double clicked! not click.');
}).on('click', function () {
clearTimeout(clickTimeout);
clickTimeout = setTimeout(function () {
if(!isDblclick) {
// here goes your click codes
console.log('a simple click.');
}
}, timeoutTiming);
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<button type="button" id="button">
click/dblclick on this to see the result
</button>

It can be achieved via following code
var clickHandler = function(e) { /* put click event handling code here */ };
var doubleclickHandler = function(e) { /* put doubleclick event handling code here */ }
const maxMsBetweenClicks = 300;
var clickTimeoutId = null;
document.addEventListener("dblclick", handleDoubleClick);
document.addEventListener("click", handleSingleClick);
function handleSingleClick(e){
clearTimeout(clickTimeoutId);
clickTimeoutId = setTimeout( function() { clickHandler(e);}, maxMsBetweenClicks);
}
function handleDoubleClick(e){
clearTimeout(clickTimeoutId);
doubleclickHandler(e);
}

I know this is old as heck, but thought I'd post anyhow since I just ran into the same problem. Here's how I resolved it.
$('#alerts-display, #object-display').on('click', ['.item-data-summary', '.item-marker'], function(e) {
e.preventDefault();
var id;
id = setTimeout(() => {
// code to run here
return false;
}, 150);
timeoutIDForDoubleClick.push(id);
});
$('.panel-items-set-marker-view').on('dblclick', ['.summary', '.marker'], function(e) {
for (let i = 0; i < timeoutIDForDoubleClick.length; i++) {
clearTimeout(timeoutIDForDoubleClick[i]);
}
// code to run on double click
e.preventDefault();
});

Here is my simple solution to prevent the second click. Of course, I could restart the timeout when a double click detected, but in reality I never need it.
clickTimeoutId = null;
onClick(e) {
if (clickTimeoutId !== null) {
// Double click, do nothing
return;
}
// Single click
// TODO smth
clickTimeoutId = setTimeout(() => {
clearTimeout(clickTimeoutId);
clickTimeoutId = null;
}, 300);
}

Summarizing, to recognize the simpleClick and doubleClick events on the same element, just treat the onClick event with this method:
var EVENT_DOUBLE_CLICK_DELAY = 220; // Adjust max delay btw two clicks (ms)
var eventClickPending = 0;
function onClick(e){
if ((e.detail == 2 ) && (eventClickPending!= 0)) {
// console.log('double click action here ' + e.detail);
clearTimeout(eventClickPending);
eventClickPending = 0;
// call your double click method
fncEventDblclick(e);
} else if ((e.detail === 1 ) && (eventClickPending== 0)){
// console.log('sigle click action here 1');
eventClickPending= setTimeout(function() {
// console.log('Executing sigle click');
eventClickPending = 0
// call your single click method
fncEventClick(e);
}, EVENT_DOUBLE_CLICK_DELAY);
// } else { // do nothing
// console.log('more than two clicks action here ' + e.detail);
}
}

You can use debounce to free the single click handler from detecting the double/multiple clicks
Test at: https://jsfiddle.net/L3sajybp/
HTML
<div id='toDetect'>
Click or double-click me
</div>
<hr/>
<ol id='info'>
</ol>
JS
function debounce(func, wait, immediate) {
let timeout;
return function () {
const context = this,
args = arguments;
const later = function () {
timeout = null;
if (!immediate) func.apply(context, args);
};
const callNow = immediate && !timeout;
clearTimeout(timeout);
timeout = setTimeout(later, wait);
if (callNow) func.apply(context, args);
};
}
function debounceSingleClickOnly(func, timeout = 500) {
function eventHandler (event) {
const { detail } = event;
if (detail > 1) {
console.log('no double click for you '+ func.name);
console.log('');
return;
}
func.apply(this, arguments);
}
return debounce(eventHandler, timeout);
}
window.toDetect.addEventListener('click', debounceSingleClickOnly(handleSingleClick));
window.toDetect.addEventListener('dblclick', handleDoubleClick);
function handleS() {
console.log('S func');
console.log(this.id);
}
function handleSingleClick(event) {
console.log('single click');
const divText = document.createElement('li');
divText.appendChild(document.createTextNode('single click'));
window.info.appendChild(divText)
console.group();
console.log('this element was single-clicked: ' + event.target.id);
console.log(this.id);
console.log('');
console.groupEnd();
}
function handleDoubleClick(event) {
console.log('double click');
const divText = document.createElement('li');
divText.appendChild(document.createTextNode('double click'));
window.info.appendChild(divText);
console.group();
console.log('this element was double-clicked: ' + event.target.id);
console.log(this.id);
console.log('');
console.groupEnd();
}
Output:

const toggle = () => {
watchDouble += 1;
setTimeout(()=>{
if (watchDouble === 2) {
console.log('double' + watchDouble)
} else if (watchDouble === 1) {
console.log("signle" + watchDouble)
}
watchDouble = 0
},200);
}

ASP.NET Post-Back and window.onload

I got a function which checks if some input fields are changed:
var somethingchanged = false;
$(".container-box fieldset input").change(function() {
somethingchanged = true;
});
And a function which waits on window.onload and fires this:
window.onbeforeunload = function(e) {
if (somethingchanged) {
var message = "Fields have been edited without saving - continue?";
if (typeof e == "undefined") {
e = window.event;
}
if (e) {
e.returnValue = message;
}
return message;
}
}
But if I edit some of the fields and hit the save button, the event triggers, because there is a post-back and the fields have been edited. Is there anyway around this, so the event does not fire upon clicking the save button?
Thanks

When I do this pattern I have a showDirtyPrompt on the page. Then whenever an action occurs which I don't want to go through the dirty check I just set the variable to false. You can do this on the client side click event of the button.
The nice thing about this is that there might be other cases where you don't want to prompt, the user you might have other buttons which do other post backs for example. This way your dirty check function doesn't have to check several buttons, you flip the responsability around.
<input type="button" onclick="javascript:showDirtyPrompt=false;".../>
function unloadHandler()
{
if (showDirtyPrompt)
{
//have your regular logic run here
}
showDirtyPrompt=true;
}

Yes. Check to see that the button clicked is not the save button. So it could be something like
if ($this.id.not("savebuttonID")) {
trigger stuff
}

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