<div id="dynamicInput">
   <div id="duplicater">
      <input type="text" placeholder="Event Title" name="title">
      <input type="text" placeholder="url" name="url">
   </div>
</div>

var i = 0;
  var original = document.getElementById('duplicater');

  function duplicate() {
    var clone = original.cloneNode(true);
    clone.id = "duplicate" + ++i;
    original.parentNode.appendChild(clone);
}