I've a simple code as following:
<html>
<body>
<div id="div1">
<input class="input1" type="text" value="click me 1" />
</div>
<script type="text/javascript">
$('.input1').click( function() { alert('clicked'); });
$('#div1').append('<input class="input1" type="text" value="click me 2" />');
</script>
</body>
</html>
I found that the 2nd textbox, which was appended to the "#div1", didn't get the click respond which is associated to the class "input1".
what am I missing? please advise me, thank you very much.
You should use event delegation with the .on() method...
$('#div1').on('click','.input1',function(...
This places the handler on #div1. When clicks happen inside of it, the '.input1' selector is run, and if the element clicked matches, the handler is invoked.
Or in older versions of jQuery (pre 1.7), use .delegate().
$('#div1').delegate('.input1','click',function(...
jQuery Live Function
: Attach an event handler for all elements which match the current selector, now and in the future.
When you are trying to bind the click event on .input1, it's not available yet, thus the bind will fail.
To fix it, you should use on:
$('#div1').on('click', '.input1', function(){alert('clicked')})
$('.something').click() appends the click listener/callback to anything that is currently in the dom.
When you have elements that were created after dom ready, you can use $('.something').live('click', function() { ... }); to do exactly the same thing for those newly created elements.
But if you're using the newest version of jQuery, use .on(...) because live was recently deprecated.
click and all of the other synonyms for bind only work for elements that exist when the function is called. If you want to also handle ones that may get created in the future, you either have to hook them up when you create them (usually a pain), or use event delegation. Event delegation works by hooking the event on a container of some kind that you're going to put the elements in, and then relies on how events bubble up the DOM from child to parent.
jQuery has excellent support for event delegation in its delegate and (more recently) on functions:
// `delegate` (jQuery 1.4.2 and later)
$("selector for container").delegate(".input1", "click", function() {
// I'll be called when there's a click on anything matching the
// selector ".input1" contained by the container
});
// `on` (jQuery 1.7.0 and later; note that the param order is different from `delegate`)
$("selector for container").on("click", ".input1", function() {
// I'll be called when there's a click on anything matching the
// selector ".input1" contained by the container
});
If the only common container the elements will have is the document itself, that's fine, you can use document as the container. (jQuery has the live function for that, but it's deprecated and it currently just calls on for you.) But in general, the more targeted you can be with the container, the better, from both a performance perspective and a code clarity perspective. For instance, use the form if you're adding form elements to a form; use the table if adding elements to a table. Etc.
Use the jQuery Live function as stated by Achmet.
This is needed because the second input field is created at run-time after the dom has been loaded.
Related
I have an input type="image". This acts like the cell notes in Microsoft Excel. If someone enters a number into the text box that this input-image is paired with, I setup an event handler for the input-image. Then when the user clicks the image, they get a little popup to add some notes to the data.
My problem is that when a user enters a zero into the text box, I need to disable the input-image's event handler. I have tried the following, but to no avail.
$('#myimage').click(function { return false; });
jQuery ≥ 1.7
With jQuery 1.7 onward the event API has been updated, .bind()/.unbind() are still available for backwards compatibility, but the preferred method is using the on()/off() functions. The below would now be,
$('#myimage').click(function() { return false; }); // Adds another click event
$('#myimage').off('click');
$('#myimage').on('click.mynamespace', function() { /* Do stuff */ });
$('#myimage').off('click.mynamespace');
jQuery < 1.7
In your example code you are simply adding another click event to the image, not overriding the previous one:
$('#myimage').click(function() { return false; }); // Adds another click event
Both click events will then get fired.
As people have said you can use unbind to remove all click events:
$('#myimage').unbind('click');
If you want to add a single event and then remove it (without removing any others that might have been added) then you can use event namespacing:
$('#myimage').bind('click.mynamespace', function() { /* Do stuff */ });
and to remove just your event:
$('#myimage').unbind('click.mynamespace');
This wasn't available when this question was answered, but you can also use the live() method to enable/disable events.
$('#myimage:not(.disabled)').live('click', myclickevent);
$('#mydisablebutton').click( function () { $('#myimage').addClass('disabled'); });
What will happen with this code is that when you click #mydisablebutton, it will add the class disabled to the #myimage element. This will make it so that the selector no longer matches the element and the event will not be fired until the 'disabled' class is removed making the .live() selector valid again.
This has other benefits by adding styling based on that class as well.
This can be done by using the unbind function.
$('#myimage').unbind('click');
You can add multiple event handlers to the same object and event in jquery. This means adding a new one doesn't replace the old ones.
There are several strategies for changing event handlers, such as event namespaces. There are some pages about this in the online docs.
Look at this question (that's how I learned of unbind). There is some useful description of these strategies in the answers.
How to read bound hover callback functions in jquery
If you want to respond to an event just one time, the following syntax should be really helpful:
$('.myLink').bind('click', function() {
//do some things
$(this).unbind('click', arguments.callee); //unbind *just this handler*
});
Using arguments.callee, we can ensure that the one specific anonymous-function handler is removed, and thus, have a single time handler for a given event. Hope this helps others.
maybe the unbind method will work for you
$("#myimage").unbind("click");
I had to set the event to null using the prop and the attr. I couldn't do it with one or the other. I also could not get .unbind to work. I am working on a TD element.
.prop("onclick", null).attr("onclick", null)
If event is attached this way, and the target is to be unattached:
$('#container').on('click','span',function(eo){
alert(1);
$(this).off(); //seams easy, but does not work
$('#container').off('click','span'); //clears click event for every span
$(this).on("click",function(){return false;}); //this works.
});
You may be adding the onclick handler as inline markup:
<input id="addreport" type="button" value="Add New Report" onclick="openAdd()" />
If so, the jquery .off() or .unbind() won't work. You need to add the original event handler in jquery as well:
$("#addreport").on("click", "", function (e) {
openAdd();
});
Then the jquery has a reference to the event handler and can remove it:
$("#addreport").off("click")
VoidKing mentions this a little more obliquely in a comment above.
If you use $(document).on() to add a listener to a dynamically created element then you may have to use the following to remove it:
// add the listener
$(document).on('click','.element',function(){
// stuff
});
// remove the listener
$(document).off("click", ".element");
To remove ALL event-handlers, this is what worked for me:
To remove all event handlers mean to have the plain HTML structure without all the event handlers attached to the element and its child nodes. To do this, jQuery's clone() helped.
var original, clone;
// element with id my-div and its child nodes have some event-handlers
original = $('#my-div');
clone = original.clone();
//
original.replaceWith(clone);
With this, we'll have the clone in place of the original with no event-handlers on it.
Good Luck...
Updated for 2014
Using the latest version of jQuery, you're now able to unbind all events on a namespace by simply doing $( "#foo" ).off( ".myNamespace" );
Best way to remove inline onclick event is $(element).prop('onclick', null);
Thanks for the information. very helpful i used it for locking page interaction while in edit mode by another user. I used it in conjunction with ajaxComplete. Not necesarily the same behavior but somewhat similar.
function userPageLock(){
$("body").bind("ajaxComplete.lockpage", function(){
$("body").unbind("ajaxComplete.lockpage");
executePageLock();
});
};
function executePageLock(){
//do something
}
In case .on() method was previously used with particular selector, like in the following example:
$('body').on('click', '.dynamicTarget', function () {
// Code goes here
});
Both unbind() and .off() methods are not going to work.
However, .undelegate() method could be used to completely remove handler from the event for all elements which match the current selector:
$("body").undelegate(".dynamicTarget", "click")
I know this comes in late, but why not use plain JS to remove the event?
var myElement = document.getElementById("your_ID");
myElement.onclick = null;
or, if you use a named function as an event handler:
function eh(event){...}
var myElement = document.getElementById("your_ID");
myElement.addEventListener("click",eh); // add event handler
myElement.removeEventListener("click",eh); //remove it
This also works fine .Simple and easy.see http://jsfiddle.net/uZc8w/570/
$('#myimage').removeAttr("click");
if you set the onclick via html you need to removeAttr ($(this).removeAttr('onclick'))
if you set it via jquery (as the after the first click in my examples above) then you need to unbind($(this).unbind('click'))
All the approaches described did not work for me because I was adding the click event with on() to the document where the element was created at run-time:
$(document).on("click", ".button", function() {
doSomething();
});
My workaround:
As I could not unbind the ".button" class I just assigned another class to the button that had the same CSS styles. By doing so the live/on-event-handler ignored the click finally:
// prevent another click on the button by assigning another class
$(".button").attr("class","buttonOff");
Hope that helps.
Hope my below code explains all.
HTML:
(function($){
$("#btn_add").on("click",function(){
$("#btn_click").on("click",added_handler);
alert("Added new handler to button 1");
});
$("#btn_remove").on("click",function(){
$("#btn_click").off("click",added_handler);
alert("Removed new handler to button 1");
});
function fixed_handler(){
alert("Fixed handler");
}
function added_handler(){
alert("new handler");
}
$("#btn_click").on("click",fixed_handler);
$("#btn_fixed").on("click",fixed_handler);
})(jQuery);
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<button id="btn_click">Button 1</button>
<button id="btn_add">Add Handler</button>
<button id="btn_remove">Remove Handler</button>
<button id="btn_fixed">Fixed Handler</button>
I had an interesting case relevant to this come up at work today where there was a scroll event handler for $(window).
// TO ELIMINATE THE RE-SELECTION AND
// RE-CREATION OF THE SAME OBJECT REDUNDANTLY IN THE FOLLOWING SNIPPETS
let $window = $(window);
$window.on('scroll', function() { .... });
But, to revoke that event handler, we can't just use
$window.off('scroll');
because there are likely other scroll event handlers on this very common target, and I'm not interested in hosing that other functionality (known or unknown) by turning off all of the scroll handlers.
My solution was to first abstract the handler functionality into a named function, and use that in the event listener setup.
function handleScrollingForXYZ() { ...... }
$window.on('scroll', handleScrollingForXYZ);
And then, conditionally, when we need to revoke that, I did this:
$window.off('scroll', $window, handleScrollingForXYZ);
The janky part is the 2nd parameter, which is redundantly selecting the original selector. But, the jquery documentation for .off() only provides one method signature for specifying the handler to remove, which requires this middle parameter to be
A selector which should match the one originally passed to .on() when attaching event handlers.
I haven't ventured to test it out with a null or '' as the 2nd parameter, but perhaps the redundant $window isn't necessary.
I have an input type="image". This acts like the cell notes in Microsoft Excel. If someone enters a number into the text box that this input-image is paired with, I setup an event handler for the input-image. Then when the user clicks the image, they get a little popup to add some notes to the data.
My problem is that when a user enters a zero into the text box, I need to disable the input-image's event handler. I have tried the following, but to no avail.
$('#myimage').click(function { return false; });
jQuery ≥ 1.7
With jQuery 1.7 onward the event API has been updated, .bind()/.unbind() are still available for backwards compatibility, but the preferred method is using the on()/off() functions. The below would now be,
$('#myimage').click(function() { return false; }); // Adds another click event
$('#myimage').off('click');
$('#myimage').on('click.mynamespace', function() { /* Do stuff */ });
$('#myimage').off('click.mynamespace');
jQuery < 1.7
In your example code you are simply adding another click event to the image, not overriding the previous one:
$('#myimage').click(function() { return false; }); // Adds another click event
Both click events will then get fired.
As people have said you can use unbind to remove all click events:
$('#myimage').unbind('click');
If you want to add a single event and then remove it (without removing any others that might have been added) then you can use event namespacing:
$('#myimage').bind('click.mynamespace', function() { /* Do stuff */ });
and to remove just your event:
$('#myimage').unbind('click.mynamespace');
This wasn't available when this question was answered, but you can also use the live() method to enable/disable events.
$('#myimage:not(.disabled)').live('click', myclickevent);
$('#mydisablebutton').click( function () { $('#myimage').addClass('disabled'); });
What will happen with this code is that when you click #mydisablebutton, it will add the class disabled to the #myimage element. This will make it so that the selector no longer matches the element and the event will not be fired until the 'disabled' class is removed making the .live() selector valid again.
This has other benefits by adding styling based on that class as well.
This can be done by using the unbind function.
$('#myimage').unbind('click');
You can add multiple event handlers to the same object and event in jquery. This means adding a new one doesn't replace the old ones.
There are several strategies for changing event handlers, such as event namespaces. There are some pages about this in the online docs.
Look at this question (that's how I learned of unbind). There is some useful description of these strategies in the answers.
How to read bound hover callback functions in jquery
If you want to respond to an event just one time, the following syntax should be really helpful:
$('.myLink').bind('click', function() {
//do some things
$(this).unbind('click', arguments.callee); //unbind *just this handler*
});
Using arguments.callee, we can ensure that the one specific anonymous-function handler is removed, and thus, have a single time handler for a given event. Hope this helps others.
maybe the unbind method will work for you
$("#myimage").unbind("click");
I had to set the event to null using the prop and the attr. I couldn't do it with one or the other. I also could not get .unbind to work. I am working on a TD element.
.prop("onclick", null).attr("onclick", null)
If event is attached this way, and the target is to be unattached:
$('#container').on('click','span',function(eo){
alert(1);
$(this).off(); //seams easy, but does not work
$('#container').off('click','span'); //clears click event for every span
$(this).on("click",function(){return false;}); //this works.
});
You may be adding the onclick handler as inline markup:
<input id="addreport" type="button" value="Add New Report" onclick="openAdd()" />
If so, the jquery .off() or .unbind() won't work. You need to add the original event handler in jquery as well:
$("#addreport").on("click", "", function (e) {
openAdd();
});
Then the jquery has a reference to the event handler and can remove it:
$("#addreport").off("click")
VoidKing mentions this a little more obliquely in a comment above.
If you use $(document).on() to add a listener to a dynamically created element then you may have to use the following to remove it:
// add the listener
$(document).on('click','.element',function(){
// stuff
});
// remove the listener
$(document).off("click", ".element");
To remove ALL event-handlers, this is what worked for me:
To remove all event handlers mean to have the plain HTML structure without all the event handlers attached to the element and its child nodes. To do this, jQuery's clone() helped.
var original, clone;
// element with id my-div and its child nodes have some event-handlers
original = $('#my-div');
clone = original.clone();
//
original.replaceWith(clone);
With this, we'll have the clone in place of the original with no event-handlers on it.
Good Luck...
Updated for 2014
Using the latest version of jQuery, you're now able to unbind all events on a namespace by simply doing $( "#foo" ).off( ".myNamespace" );
Best way to remove inline onclick event is $(element).prop('onclick', null);
Thanks for the information. very helpful i used it for locking page interaction while in edit mode by another user. I used it in conjunction with ajaxComplete. Not necesarily the same behavior but somewhat similar.
function userPageLock(){
$("body").bind("ajaxComplete.lockpage", function(){
$("body").unbind("ajaxComplete.lockpage");
executePageLock();
});
};
function executePageLock(){
//do something
}
In case .on() method was previously used with particular selector, like in the following example:
$('body').on('click', '.dynamicTarget', function () {
// Code goes here
});
Both unbind() and .off() methods are not going to work.
However, .undelegate() method could be used to completely remove handler from the event for all elements which match the current selector:
$("body").undelegate(".dynamicTarget", "click")
I know this comes in late, but why not use plain JS to remove the event?
var myElement = document.getElementById("your_ID");
myElement.onclick = null;
or, if you use a named function as an event handler:
function eh(event){...}
var myElement = document.getElementById("your_ID");
myElement.addEventListener("click",eh); // add event handler
myElement.removeEventListener("click",eh); //remove it
This also works fine .Simple and easy.see http://jsfiddle.net/uZc8w/570/
$('#myimage').removeAttr("click");
if you set the onclick via html you need to removeAttr ($(this).removeAttr('onclick'))
if you set it via jquery (as the after the first click in my examples above) then you need to unbind($(this).unbind('click'))
All the approaches described did not work for me because I was adding the click event with on() to the document where the element was created at run-time:
$(document).on("click", ".button", function() {
doSomething();
});
My workaround:
As I could not unbind the ".button" class I just assigned another class to the button that had the same CSS styles. By doing so the live/on-event-handler ignored the click finally:
// prevent another click on the button by assigning another class
$(".button").attr("class","buttonOff");
Hope that helps.
Hope my below code explains all.
HTML:
(function($){
$("#btn_add").on("click",function(){
$("#btn_click").on("click",added_handler);
alert("Added new handler to button 1");
});
$("#btn_remove").on("click",function(){
$("#btn_click").off("click",added_handler);
alert("Removed new handler to button 1");
});
function fixed_handler(){
alert("Fixed handler");
}
function added_handler(){
alert("new handler");
}
$("#btn_click").on("click",fixed_handler);
$("#btn_fixed").on("click",fixed_handler);
})(jQuery);
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<button id="btn_click">Button 1</button>
<button id="btn_add">Add Handler</button>
<button id="btn_remove">Remove Handler</button>
<button id="btn_fixed">Fixed Handler</button>
I had an interesting case relevant to this come up at work today where there was a scroll event handler for $(window).
// TO ELIMINATE THE RE-SELECTION AND
// RE-CREATION OF THE SAME OBJECT REDUNDANTLY IN THE FOLLOWING SNIPPETS
let $window = $(window);
$window.on('scroll', function() { .... });
But, to revoke that event handler, we can't just use
$window.off('scroll');
because there are likely other scroll event handlers on this very common target, and I'm not interested in hosing that other functionality (known or unknown) by turning off all of the scroll handlers.
My solution was to first abstract the handler functionality into a named function, and use that in the event listener setup.
function handleScrollingForXYZ() { ...... }
$window.on('scroll', handleScrollingForXYZ);
And then, conditionally, when we need to revoke that, I did this:
$window.off('scroll', $window, handleScrollingForXYZ);
The janky part is the 2nd parameter, which is redundantly selecting the original selector. But, the jquery documentation for .off() only provides one method signature for specifying the handler to remove, which requires this middle parameter to be
A selector which should match the one originally passed to .on() when attaching event handlers.
I haven't ventured to test it out with a null or '' as the 2nd parameter, but perhaps the redundant $window isn't necessary.
click not working after i clear and append the html inside a div using jquery.
Here is the html code
<div id="divMain">
</div>
<input id="btn" type="button" value="Clear&Add"/>
Here is the jQuery code
var a = $('<a/>').attr({'id':'aH','href':'#'}).text('Hello');
a.click(function(){
alert('hello');
});
$('#divMain').append(a);
$('#btn').click(function(){
var newA = $('#aH');
$('#divMain').html('');
$('#divMain').append(newA);
});
Here is jsfiddle
Simple click on the alert link in fiddle , it shows an alert.Now click on the Clear&Add button .And now click on alert.It doesn't work.
You need event delegation to bind the event with dynamically added elements. You also need to create elemet with id aH as you have removed the element from DOM without preserving it.
Live Demo
$(document).on('click', '#aH', function(){
alert('hello');
});
You can try adding the globally created a and you would not need to bind click again.
$('#divMain').append(a);
Delegated events have the advantage that they can process events from
descendant elements that are added to the document at a later time. By
picking an element that is guaranteed to be present at the time the
delegated event handler is attached, you can use delegated events to
avoid the need to frequently attach and remove event handlers, jQuery api
You need to use event delegation:
$('#divMain').on('click', a, function(){
alert('hello');
});
Updated Fiddle: http://jsfiddle.net/W95wV/1/
Click does not work on dynamically created elements in jQuery. In the earlier version of jQuery we could use .live('click') that has been deprecated in the recent versions. Now you can use .on to work better for dynamic elements as Adil said.
With JQuery, is it possible to add an event listener to any element that currently, or will in the future, have a particular class?
I'm working on a project that makes heavy use of contentEditable, so the DOM is changing, and elements can have classes added and removed as a result of user input.
I would like to be able to say "elements of class X should do Y when clicked", but if I understand correctly, $(".X").click(Y) will only add the event listener to elements that currently have class X.
Furthermore, if an element is no-longer part of class X, then it will still have the click event listener.
How can I do this?
Yep. What you're talking about is called event delegation. Here's an example:
$('#container').on('click', '.innerElement', function(){
/// Do stuff
});
In your case, #container would be an element that is known to exist on page load which will contain the child elements you care about (either now or in the future). This approach takes advantage of event bubbling in the DOM.
As another poster mentioned, the live method will also work -- but it has been deprecated in jQuery 1.7, and is generally not as performant as using more selective delegation (such as the example above).
you'll want to use event delegation. jquery 1.7 has made this more abstract than previous versions, but it looks something like this:
$("#myWrappingElement").on("click", ".myclass", function(event){
alert($(this).text());
});
this basically adds a click event listener to the #myWrappingElement element, and jquery will automagically look to see what the original event target was and fire the proper function. this means you can add or remove .myclass elements and still have events fire on them.
the jQuery live() method swill allow to have a "live" action listener - so if new DOM elements match the selector, they will be attached to the action listener. For example:
$(".X").live("click", function(){
alert('some action');
});
See the documentation here for more info: http://api.jquery.com/live/
I'm not sure that the second part of your question about keeping the action listener attached after removing the class os possible - someone else might have a solution though.
I have an group of checkboxes with id's starting with somename and I want catch the click event of these checkboxes. Previously I have done this through jQuery. i.e.:
$("input[id^='somename']").click(function(){
// my code follows here
})
but this is not working this time around. Why?
P.S. The element is created via JavaScript after the page is fully loaded after making some ajax request. I don't know if this may be the problem?
just use live if elements are created after the page is loaded.
$("input[id^='somename']").live('click', function(){ // my code follows here })
P.S : Your search selector is "somename" but you search it on the attribute ID, are you sure that you don't want :
$("input[name^='somename']").live('click', function(){ // my code follows here })
instead?
This indeed could be the problem. Replace .click with .live()
$("input[id^='somename']").live('click', function(){ // my code follows here })
and you should be fine.
Since a call to .click is just a shortcut for .bind('click', fnc), this will not work if the element is not in the DOM when calling this. Even better than using .live() would be to use .delegate(). Have a read:
.live(), .delegate()
Using the standard binding functions only works on elements that exist at the time of the bind. You need to use something called event delegation, where elements further up the DOM tree are notified of events on descendant elements. The best way to do this is with .delegate():
$('#containingElement').delegate("input[id^='somename']", 'click', function(){
// your code here
});
This assumes that you have an element #containingElement that contains all the elements that you want to capture the events on.
NB that other answers recomment live. live and delegate use the same backend code, but for various reasons delegate is more efficient.
I believe that because you want this applied to dynamically created elements in the DOM you are going to have to use the the jQuery .live() method:
$("input[id^='somename']").live('click', function(e) {
// Your code
});
Instead of .click() try .change() event.