closest(selector) {
    var matches = this.matches || this.mozMatchesSelector || this.msMatchesSelector || this.oMatchesSelector || this.webkitMatchesSelector;
    var element = this;
    while (element) {
      if (matches.call(element, selector)) {
        break;
      }
      element = element.parentElement;
    }
    return element;
  }
Returns first element matching a selector by traversing up the tree starting
from and including receiver element.

@param {string} selector - Selector of element to find.