How to find the first ancestor of an element whose sibling is particular element in jquery?

Question

<div>
  <input type="text">
  <span id="ending_point">
     <label>
        <span>
        <input type="text" id="starting_point">
           <span>
           </span>
        </span>
    </label>
  </span>
</div>

Here i want to find the ancestor of an element(here with id:starting_point) whose previous sibling is "input".Here the answer is span with id "ending_point" because it's previous sibling is "input".How to find this?

Answer 1

You can use a combination of .parents and .filter:

var $ep = $("#starting_point")
  .parents()
  .filter(function() {
    return $(this).prev().is("input");
  })
  .first();

// NB: the parents() method return all parents, CLOSEST ONE FIRST

console.log($ep);

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>

<div>
  <input type="text">
  <span id="ending_point">
    <label>
      <span>
        <input type="text" id="starting_point">
        <span></span>
      </span>
    </label>
  </span>
</div>