Do I need to unbind jquery event before remove element?

I have a page using jquery-ui-dialog. Each time the dialog opens, page contents load in using ajax. Then it binds some event using jquery "on()". When the dialog close, it will empty its content.

The question is, do I need to unbind the events on ".ajax-content" before $.empty()?

edit: concern 1. any possible degrade JS performance? if I empty() hundreds of nodes this way.

concern 2. would remove element also remove events from memory(or whatever execution/evaluation chain of jquery)?

I am not doing anything to them for now. If the dialog open/close for many times without page refresh, would it cause any problem?

Code look like this:

<div id="jquery-dialog" class="container">
  <div class="ajax-content">
    some buttons....
  </div>
</div>

------after each ajax load------------
$(".ajax-content").on("click", ".button", function(event) {
  //handles the click
});

------on dialog close------------
$("#jquery-dialog").empty();

Hey I know this is an old question but I believe the accepted answer is misleading.

Although it's correct to say that you will need to unbind events on raw JS to avoid memory leaks on old browsers (ehem IE), calling remove() or empty() will already do that for you.

So your current call to empty() should be enough, it doesn't need to be preceded by unbind()

From jQuery docs (http://api.jquery.com/empty/)

To avoid memory leaks, jQuery removes other constructs such as data and event handlers from the child elements before removing the elements themselves.

It's better to unbind but must.

Most browsers handle this correctly and remove those handlers themselves.

You can also see do-i-need-to-remove-event-listeners

Better way to handle this problem, you can use the Event Delegate.