I have a button being created after the DOM is created. That button has an action. What I'm having trouble is binding that action to the button. I have researched and people said to us the .on() function but it doesn't seem to be working. What am I missing?
http://jsfiddle.net/e7a4X/
HTML
<button id="firstClick">Click me to create another button</button>
<div id="container"></div>
Javascript
$('#firstClick').click(function() {
$('#container').append('<button class="second-button">Button after DOM</button>');
});
$('.second-button').on('click', function () {
alert("Success");
})
Working demoL http://jsfiddle.net/Metsx/ or http://jsfiddle.net/ZB2Ns/
API : .on http://api.jquery.com/on/
Now to make your event know about the click event you need .on at document or at #container level, which attaches event handlers to the currently selected set of elements in the jQuery object.
Rest should fit your need :)
Code
$('#firstClick').click(function() {
$('#container').append('<button class="second-button">Button after DOM</button>');
});
$(document).on('click', '.second-button', function () {
alert("Success");
})
You will need to tell the DOM, parent to listen to its child.
The issue is that Your new .second-button is a new element, and you have defined your .click function before the DOM actually exists.
But all DOM interactions will trigger a event propagations(bubbling), therefore you can tell #container to listen for click events coming from .second-button
Or use $(document).on to listen, since the bubbling will go all the way to the document root.
If you are a performance minimalist than you would just do #container .on, and stop the propagation from that point, since theres no need to travel to every parent node, but you might eventually need to listen it from the parent of the #container, who knows
Related
I am sorry that my origin description is not clear. I have revised my question:
I am using jQuery, as shown in the attached picture, each time I attach an event listener (e.g. click) to an element, it will fire twice. It looks like this problem is due to the jQuery debugger.
I would like to ask if there is any approach other than adding unbind() or off() before the listener to solve the problem, I have tried these approaches but it removes the listeners already attached to the elements
(e.g. I have #element1 which is created in html, then use jQuery to append two elements #element2 and #element3 to #element1, if I use
$('#element1').off('click').on('click', '#element2', function(){
//implementation
}
$('#element1').off('click').on('click', '#element3', function(){
//implementation
}
the click event of #element2 will no longer work because the click listener attached on it is removed in this situation. So I am asking if there is a better way to do it?
By the way, I am wondering where is the VM 7188 listener comes from (it looks like from jQuery debugger) and if there is anyway to remove this listener so that I no longer need to use off() every time when I write a listener, thanks.
Attached picture for duplicated listeners
It's unclear why you'd need to remove and attach a handler to #element1 just because #element2 is removed and dynamically created; you're using delegated syntax, so it's totally fine that #element2 is dynamically created. You only need to set that handler once, regardless. Example:
// Note this continues to work even as we remove and recreate #element2
$("#element1").on("click", "#element2", function() {
console.log("Got the click on #element2");
});
function tick() {
$("#element1").append("<span id='element2'>Click me</span>");
setTimeout(function() {
$("#element2").remove();
setTimeout(tick, 500);
}, 1500);
}
tick();
<div id="element1"></div>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
But to target specific handlers, you can use event namespaces, e.g.:
$('#element1').off("click.my-namespace").on('click.my-namespace', '#element2', function(){
//implementation
});
For more, see "Event names and namespaces" in the documentation.
I'm not a jquery person, but it seems to me that you are adding the handler to a child descendant and therefore the event bubbles. Instead of adding/removing listeners like this, when adding the handler to children, consider adding event.stopPropagation()
$('#element1').unbind().on('click', '#element2', function(e){
e.stopPropagation();//#element1 won't receive this anymore
//implementation
}
You can call inline function, add attr to your element
onclick="handler"
Remove old handler before bind new
$("#element1").off("click", "#element2", handler);
$("#element1").on("click", "#element2", handler);
I have a click event on the body of my document:
$("body").on('click.findElem', function(e) {
e.stopPropagation();
e.preventDefault();
self.hinter(e.target);
return false;
});
It basically catches the clicked target and does something to it. However, there are some targets that already have a click event on them, and they prevent my click from being executed at all. How do I overcome that issue? I tried unbinding it, but the click doesn't even work at all to actually execute the unbinding.
e.stopImmediatePropagation() does the job, but only if your handler executes before whatever other handler exists.
Unfortunately there is no way to insert your own handler in the first position - but you can use this nasty hack if the other handlers were bound using jQuery, too: How do you force your javascript event to run first, regardless of the order in which the events were added?
If you really need this you might want to bind an event handler in capture mode using the native DOM API: https://developer.mozilla.org/en-US/docs/Web/API/EventTarget.addEventListener
Capture handlers are triggered before bubble handlers (which are used by jQuery and most other scripts) so that way you have very high chance to execute your handler first.
try this and see demo
$( "body" ).on( "click", ".clickme:not(.clicked)", function( event ) {
$(this).addClass('clicked');
alert('here');
});
i tend to not use on and stick with the bind/unbind combo.
i have some pages that reload partial content and then has to rebind the events.
i tipically do something like this
$(".theobjectsiwant").unbind("click").bind("click", function() {
alert('hi there');
});
If you want/have to stick with the on() function, you shouldn't mix on() with unbind() and try a similar approach with .off("click").on("click")
Check here for a sample http://api.jquery.com/off/
I'm trying to trigger my own custom events as global events, so that anything on my page can listen to them and react, however, for dynamically added content it's not working. See my fiddle at: http://jsfiddle.net/6TMkG/8/
As far as I understand, the event is triggered for any element in the page that jQuery knows has a handler for it, and it seems it doesn't trigger the event for the li's even though they do have a handler.
Anyone know how to get around this behaviour?
try this
$("#b2").click(function() {
//$.event.trigger("randomEvent");
$('li').trigger('randomEvent');
});
If you want global event, then you could bind the event handler on document, and trigger it on any element in the document.
$(document).on('randomEvent', callback);
$('ul').click(function() {
$(this).trigger("randomEvent");
});
Sorry I completely missed that.. I did not see the first part of your question.. Custom events.. Looks like you are associating the randomEvent but you are not triggering that event when that is associated with it..
Make sure you add the trigger Event in the Document.Ready function so that the evnet handler is associated with as and when the element is available.
i got a problem
<div id='parent'>
<div id='child'>
</div>
</div>
what i want is when the child is clicked addClass,and when the rest of parent is clicked removeClass,so when i try to do
$('#child').click(function(){
$(this).addClass();
})
$('#parent').click(function(){
$('#child').removeClass();
})
its not working i think its because the child is actually inside the parent,so when the child is clicked the parent clicked right?
so how can i do that?
try this:
$('#child').click(function(evt){
evt.stopPropagation();
$(this).addClass("myClass");
});
You could use event.stopPropagation to prevents the event from bubbling up the DOM tree, preventing any parent handlers from being notified of the event.
$('#child').click(function(e){
e.stopPropagation();
$(this).addClass();
});
Several users have already suggested a good solution - here's an explanation of why it works:
When you click an HTML element (actually a DOM object...), the click event "bubbles" all the way up to the root element. For example, a click in #child also triggers a click in #parent, as you expected.
To stop this behavior, you need to call .stopPropagation() on the click event - that will tell the browser that you do not want the event to propagate, but keep it "local". Basically, when you've handled it here, you're done with it and don't want to see it again.
Conveniently, jQuery event handlers take the event as the first argument, so if you assign any function with the signature function (e) { ... }, you can stop event propagation by e.stopPropagation(); as others have suggested. In your case, you want
$('#child').click(function(e){
$(this).addClass();
e.stopPropagation();
});
$('#parent').click(function(){
$('#child').removeClass();
});
I have HTML similar to the following in my page
<div id="someDiv">
<img src="foo.gif" class="someImg" />
</div>
The wrapper div is set up such that when it is clicked, it's background-color changes using the following jQuery code.
$("div").click(function(event){
$(this).css("background-color", "blue");
});
I also have some jQuery associated with my img that will do some other function (for the sake of argument I am going to display and alert box) like so:
$("img[class=someImg]").click(function(event){
alert("Image clicked");
});
The issue I have come across is that when I click on the img, the event associated with the div is also triggered. I'm pretty sure that this is due to the way that jQuery (or indeed JavaScript) is handling the two DOM elements - clicking the img would require you to also technically click the div, thus triggering both events.
Two questions then really:
Is my understanding of the
DOM/JavaScript flawed in some way or
is this actually how things are
occurring?
Are there any jQuery methods that
would allow me to perform actions on
a child element without invoking
those associated with its parent?
That is known as event bubbling, you can prevent it with stopPropagation():
$("img[class=someImg]").click(function(event){
alert("Image clicked");
event.stopPropagation();
});
.
Is my understanding of the DOM/JavaScript flawed in some way or
is this actually how things are
occurring?
That is because of what is known event bubbling.
Are there any jQuery methods that would allow me to perform actions
on a child element without invoking
those associated with its parent?
Yes, you need stopPropagation()
No, this is by design. Events bubble up through the entire dom, if you put another handler on body, it would fire too
Yes :) JQuery normalizes the event object, so adding event.stopPropagation() in your img click handler will give you the behavior you expect on all browsers
The problem you just facing is called "event bubbling". That means, if you click on a nested
element, that click event will "bubble up" the DOM tree.
If other elements also are bound to an click event, their listeners will fire aswell.
Solution to prevent this is called:
stopPropagation()
which is used within your event handler
$("img[class=someImg]").click(function(event){
event.stopPropagation();
alert("Image clicked");
});
This is what's called event bubbling, and you can stop it to get the behavior you want with .stopPropagation() (or return false; if you want to stop the event completely, including handlers on the same level), like this:
$("img[class=someImg]").click(function(event){
alert("Image clicked");
event.stopPropagation();
});
You can view a demo here, comment it out and click run again to see the difference.
The short version is that when most event types happen, they happen on the immediate element, then bubble up the DOM, occurring on each parent as they go. This is not jQuery specific at all, native JavaScript does this. If you're more curious, I'd read the linked article, it has a great explanation of what's going on.