How to check if click event is already bound - JQuery

Question

I am binding a click event with a button       myButton   bind  click    onButtonClicked     In one scenario  this is getting called multiple times  so when I do a trigger I see multiple ajax calls which I want to prevent   How do I bind only if its not bound before

User · Answer

I wrote a very tiny plugin called  once  which do that  Execute off and on in element     fn once   function a  b        return this each function               this  off a  on a b                And simply     element  once  click   function

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if      btn   data  events      undefined  amp  amp      btn   data  events   click    undefined          do nothing as the click event is already there   else           btn   click function  e            alert  test

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One more way - mark such buttons with a CSS class and filter       myButton not  bound    addClass  bound   bind  click    onButtonClicked     In recent jQuery versions replace bind with on       myButton not  bound    addClass  bound   on  click    onButtonClicked

User · Answer

Why not use this  unbind   before bind        myButton   unbind   bind  click    onButtonClicked

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Try   if  typeof     myButton   click      function             myButton   click onButtonClicked

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Based on  konrad-garus answer  but using data  since I believe class should be used mostly for styling   if   el data  bound        el data  bound   true     el on  event   function e

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Here s my version   Utils eventBoundToFunction   function  element  eventType  fCallback        if   element     element data  events       element data  events   eventType      fCallback            return false             for  runner in element data  events   eventType             if  element data  events   eventType  runner  handler    fCallback                return true                        return false       Usage   Utils eventBoundToFunction okButton   click   handleOkButtonFunction

User · Answer

To avoid to check bind unbind  you can change your approach  Why don t you use Jquery  on      Since Jquery 1 7   live     delegate   is deprecated  now you can use  on   to      Attach an event handler for all elements which match the current selector  now and in the future   It means that you can attach an event to a parent element that is still existing and attach children elements whether they are present or not   When you use  on   like this       Parent   on  click     myButton   onButtonClicked     You catch event click on parent and it search child   myButton  if exists     So when you remove or add a child element  you do not have to worry about whether to add or remove the event binding

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As of June 2019  I ve updated the function  and it s working for what I need     fn isBound   function  type        var data      data   this  0    events         if  data type      undefined    data length     0            return false            return true

User · Answer

If using jQuery 1 7    You can call off before on       myButton   off  click   onButtonClicked     remove handler                on  click   onButtonClicked      add handler   If not   You can just unbind it first event       myButton   unbind  click   onButtonClicked    remove handler                bind  click   onButtonClicked      add handler

User · Answer

JQuery has solution        foo    one   click   function       alert   This will be displayed only once             equivalent        foo    on   click   function  event       alert   This will be displayed only once           this   off  event

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Update 24 Aug  12  In jQuery 1 8  it is no longer possible to access the element s events using  data  events     See this bug for details    It is possible to access the same data with jQuery  data elem   events    an internal data structure  which is undocumented and therefore not 100  guaranteed to remain stable   This shouldn t  however  be a problem  and the relevant line of the plugin code above can be changed to the following   var data   jQuery  data this 0    events   type       jQuery events are stored in a data object called events  so you could search in this   var button       myButton    if  -1       inArray onButtonClicked  button data  events   click         button click onButtonClicked       It would be best  of course  if you could structure your application so this code only gets called once     This could be encapsulated into a plugin     fn isBound   function type  fn        var data   this data  events   type        if  data     undefined    data length     0            return false             return  -1       inArray fn  data         You could then call   var button       myButton    if   button isBound  click   onButtonClicked         button click onButtonClicked

User · Answer

The best way I see is to use live   or delegate   to capture the event in a parent and not in each child element   If your button is inside a  parent element  you can replace       myButton   bind  click    onButtonClicked    by      parent   delegate   myButton    click    onButtonClicked    even if  myButton doesn t exist yet when this code is executed

[jquery] How to check if click event is already bound - JQuery

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