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Best way to remove an event handler in jQuery?

Posted by: admin November 2, 2017 Leave a comment

Questions:

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; });
Answers:

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');

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Answers:

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.

Questions:
Answers:

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

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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.

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Answers:

maybe the unbind method will work for you

$("#myimage").unbind("click");

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Answers:

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)

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Answers:

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.

});​

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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" );

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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.

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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
}

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Answers:

Best way to remove inline onclick event is $(element).prop('onclick', null);

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This also works fine .Simple and easy.see http://jsfiddle.net/uZc8w/570/

$('#myimage').removeAttr("click");

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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'))

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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")

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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>

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Answers:

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

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Answers:

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.