jQuery click function not working with setInterval

Question

I'm calling an internal web page to my div every second with setInterval (that is to say reloading div). It's working fine but users should click a button inside of that reloading div and it fails.

This is my code:

HTML:

<ul class="folio-list" id="buttons"></ul>

JavaScript:

   <script type="text/javascript">
    window.onload = function() {
      setInterval(function(){ $("#buttons").load("<?php echo site_url('buttons'); ?>"); }, 1000);
    };
    </script>

And this is the calling page's HTML:

<li class="tile-large pink">
            <div id="time">
              <h2 class="Hours">30 Minutes </br> 1 BTC</h2>
                <br />
              <div class="timer">
                  <div class="col-xs-4">
                    <div class="form-group">
                      <input type="text" class="form-control" id="hrs" value="0">
                      <label for="firstname" class="col-sm-2 control-label">Hrs</label>
                    </div>
                  </div>

                   <div class="col-xs-4">
                    <div class="form-group">
                      <input type="text" class="form-control" id="mnt" value="0">
                      <label for="firstname" class="col-sm-2 control-label">Mnt</label>
                    </div>
                  </div>

                   <div class="col-xs-4">
                    <div class="form-group">
                      <input type="text" class="form-control" id="sec" value="0">
                      <label for="firstname" class="col-sm-2 control-label">Sec</label>
                    </div>
                  </div>

              </div>
              <br />
              <h3 class="winner-name"> Nobody </h3>
              <button class="btn btn-success pay" data-id="2">Get Ticket!</button>
            </div>


        </li>

I'm trying to make this part clickable

<button class="btn btn-success pay" data-id="2">Get Ticket!</button>

with this JavaScript code below:

<script type="text/javascript">
$('.pay').click(function() {
   var id = $(this).attr('data-id');
   $.ajax({
     url: "<?php echo site_url('pay'); ?>" + "/" + id,
     type: 'POST',
     success: function(answer) {
             $('#answer').html(answer);
         }
   });
 });
 </script>

When I disable reloading thing, button working fine. I'm sure that the problem is setInterval part.

Thanks in advance.