code: function searchParent(el, parentClass) {
      var found = false;
      var parentElement = el.parentNode;
      while (parentElement && found === false) {
        if (hasClass(parentElement, parentClass) === true) {
          found = true;
        } else {
          parentElement = parentElement.parentNode;
        }
      }
      if (found === true) {
        return parentElement.getAttribute('id');
      } else {
        return '';
      }
    }
docs: /* gets an element el, search if it is child of parent class, returns id of the parent