Disable AddEventListener On Submit

Question

I am trying to disable the function I pass to addEventListener when the user clicks on submit. I put code in to prevent user from leaving page if they have entered

Answer 1

Update

To prompt the user before leaving a form:

window.onbeforeunload = function(){
  return 'Are you sure you want to leave?';
};

^{See this post}

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Use the required attribute on each field and you won't need to do all of that. The following demo will refuse any attempts to submit it's form if there's a blank field. It will send to a live test server and a response will be displayed verifying a successful submission.

Demo

window.onbeforeunload = function(){
  return 'Are you sure you want to leave?';
};

label {
  display: inline-block;
  width: 75px
}

[type=submit] {
  margin-left: 200px
}

  Name: 

  Cell: 

  Date: