Check if an element has event listener on it No jQuery

Question

How to check if an element has event listener on it  if I use an inline function on it like the code below  Because I have a function that recalls the function and add the event listener  but it cause to have duplication event listener causing it to trigger a function twice  How can I check it so I can prevent it to add an event listener if is it already exist     for  var a   0 a lt formFieldInput length a          if formFieldInput a  hasAttribute  name    amp  amp  formFieldInput a  attributes title value      Valid Until             formFieldInput a  addEventListener  click  function event                toggleFieldList event  show

User · Accepted Answer

There is no JavaScript function to achieve this. However, you could set a boolean value to true when you add the listener, and false when you remove it. Then check against this boolean before potentially adding a duplicate event listener.

Possible duplicate: How to check whether dynamically attached event listener exists or not?

User · Answer

Nowadays  2016  in Chrome Dev Tools console  you can quickly execute this function below to show all event listeners that have been attached to an element   getEventListeners document querySelector  your-element-selector

User · Answer

You don t need to  Just slap it on there as many times as you want and as often as you want  MDN explains identical event listeners      If multiple identical EventListeners are registered on the same   EventTarget with the same parameters  the duplicate instances are   discarded  They do not cause the EventListener to be called twice  and   they do not need to be removed manually with the removeEventListener   method

[javascript] Check if an element has event listener on it. No jQuery

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