jQuery on click not working on iPhone (touch devices)

I used the touchstart event with the click , it did the job for me

 $(document).on("click touchstart tap", "#button_X", function (){
//your code here      
 });

By default, divs are not a "clickable" elements. But adding cursor: pointer; makes iOS treat it as clickable.

So all you need to do is add

.close {
    cursor: pointer;
}

to your CSS and then it will work.

Proof here: https://jsfiddle.net/27ezjrqr/6/

$(document).on('click', '.close', function() {
  alert('hello');
});
.close {
  cursor: pointer;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="close">
  Click here
</div>