An jQuery function to get the closest descendant element which matches the specified selector.

closestDescendant.js

/**
 * closestDescendant
 * An jQuery function to get the closest descendant element which matches the specified selector.
 * The search strategy is breadth-first.
 */
;(function () {
  $.fn.closestDescendant = function (selector) {
    var $elem = $();
    
    this.each(function () {
      var matchedSet = $(this).find(selector).toArray();
      var queue = $(this).children().toArray();
  
      while (queue.length) {
        var $current = $(queue.shift());
        if ($.inArray($current[0], matchedSet) > -1) {
          $elem = $elem.add($current);
          break;
        }
        queue = queue.concat($current.children().toArray());
      }
    });

    return $elem;
  }
})();