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'm building a library without depending on Jquery in order to better my javascript knowledge. However in writing tests for the library I'm using some Jquery methods.
I have a test that triggers events listeners added using the native EventTarget.addEventListener method using Jquery's .trigger method.
var elem = document.getElementById('square');
elem.addEventListener('click', function () {
alert('click');
});
elem.addEventListener('mouseover', function () {
alert('mouseover');
});
$(elem).trigger('click');
$(elem).trigger('mouseover');
When I trigger two different events on the same element, only one handler fires.
This can be observed in this JSFiddle
Can someone explain why this happens and how to fix it?
If you are using addEventListener, you can't use jQuery's trigger method. (It will work for some events like click, but not for everyone, like mouseover, as you noticed). This is also explained in this question.
You have two options. Either you use jQuery's on event like this:
$(elem).on('mouseover', function () {
alert('mouseover');
});
Or the other is to trigger the event without using jQuery. You can check this question to do that.
I have a fiddle which creates a viewer for a set of data. If you are looking at the javascript, it will look at 3 lines, if you search for SEARCH_HERE
$("body").append("TEMPLATE<hr />Maintaining Object").append($maintence);
//$("body").html($maintence);
//$("body").html($_table);
The fiddle is located at: http://jsfiddle.net/fallenreaper/wFGW6/1/
The first one will show the TEMPLATE on the page and then adding new ITEMS will all have working events when doing
var $data = $_table.clone(true,true);
in the addBlock() function.
If you only uncomment the second line, it will JUST show the maintainer item.
When you add items [+], you will show the form, but the events would not be there.
I was thinking that since $_table is removed from the page, the events are not there any longer. The 3rd line, pretty much reappends $_table to the document, and the events are not there.
IS this suppose to be like this? Should i instead just create a wrapper function which is executed inside of addBlock() to attach all the handlers accordingly?
This is rather odd.
EDIT:
One answer, pointed to delegated events, which seems like it could work. There is an issue though that seems to set $(this) to a new object, the body tag, instead of the selected element.
inside of a click event would be redefined as:
$("body").on("click", $expander, function(){...});
//instead of:
//$expander.click(function(){...});
I was thinking to just do something like left-hand assignment, something like:
$(this) = $expander;
but according to a website, left-hand assignment doesnt work. (http://hungred.com/how-to/tutorial-override-this-object-javascript/). They did point me in a direction which would be VERY useful.
function example(eventHandler){
ALL MY CODE.
}
$("body").on("click", $expander, function(event){
example.call($expander, event);
});
Does this look feasible, or should i be planning another route?
You can use jQuery's .on() to do some event delegation. Your code is too long for me to read and edit, but in a nutshell rather than having $add.click(function() { ... }) you bind the event listener to the parent or body $("body").on("click", ".addNew", function() { ... })
There is a 'View' in the model with the event click. After using the Quicksand effects plug-in for jQuery, the objects loose their event handlers. I have tried to add the listener for the event with standard methods in backbone.js:
events: {
"click .objContact" : "openChat"
}
and the same tools jQuery delegate:
var self=this;
this.$el.delegate('.objContact','click', function(){
self.openChat();
});
and live:
var self=this;
this.$el.find('.objContact').live('click', function(){
self.openChat();
});
but the click event disappears.
What could be the problem? And how do I solve it?
UPD: Calling 'Quicksand' is in Backbone.Router (subject to change is obtained directly by means of jQuery, not Backbone), so changes are not handled in Backbone.View
UPD 2: The problem is solved in the following way - by moving the handling of the click event from the View-model to View-collection. And treated with live (did not work in on)
Simple Answer: instead of linking the function to the link with the classic ajax method that is
$('a.oldJqueryClass').click(function(){....
you need to make that function standalone, declaring a new function
function myfunction(params) {alert(params);}
than in the link you call that with the old school way:
Click here
In this way the cloned element will contain itself the call to the function and you can forget about restoring the dom integrity broken by the cloning of quicksand.
I did it in my project, it works fine.
Do a call to delegateEvents() after the related DOM entries have changed or become overwritten. In a traditional Backbone app this is typically done in the render method, but you probably need for figure out when and where quicksand does it's magic (I do not know anything about it), and call delegateEvents that will reactivate the events for the current elements in the DOM.
I have a script that does graphing, using jqplot. It works fine when the document is loaded rendering each graph using jquery's .each method. However, the problem lies when I replace the div with another one when a bar is clicked. It is suppose to render another graph in the position of the old graph. It changes the graph but does not execute the script.
The script that loads the items has this function to change all divs to graphs:
$("div.barchart").each(function(){
barChart($(this).attr("id"),$(this).attr("data-xmlurl"));
});
is there another way to do this so that it would work when a div is changed too?
Update:
Rails generates a script that is ran. However, it doesn't seem to work when I have this:
chart$=$("#<%=params[:chart_id]%>");
chart$.replaceWith("<%=escape_javascript(render :partial=>"chart_partial"}%>");
barChart(chart$.get(0).attr("id"),chart$.get(0).attr("data-xmlurl"));
Note:
For reference, the actual source code can be found in the jquery_cheats project
Perhaps you could add a listener on the parent element? Is it OK if the barChart() function gets called more than once?
Maybe something like this:
$("div.barchart").parent().on("DOMSubtreeModified", function(e) {
// (or maybe use DOMNodeInserted event instead)
$("div.barchart[id][data-xmlurl]").each(function() {
barChart($(this).attr("id"),$(this).attr("data-xmlurl"));
});
});
You can check out my jsFiddle for this here.
On the current application I'm working on, I'm stuck with version 1.5.2. To get around this, I would unbind and rebind my event and load the initialization in both "ajaxComplete" and "ready". I wasn't able to get the DOM to automatically rebind the event. Delegate is suppose to work like "on", but in my instance I still had to use the below logic.
In short, it would look something like this.
$(document).ready(function () {
InitSomethingCool();
});
$(document).ajaxComplete(function() {
InitSomethingCool();
});
function InitSomethingCool(){
$(".something").unbind('click').click(function(e) {
//Unbind and rebind click event.
alert('You clicked me!');
});
}
Reference:
http://api.jquery.com/on/
http://api.jquery.com/delegate/