Use with event delegate when jquery is not available.

filter target by class

/**
   * filter the event target for the nya-bs-option element.
   * Use this method with event delegate. (attach a event handler on an parent element and listen the special children elements)
   * @param target event.target node
   * @param parent {object} the parent, where the event handler attached.
   * @return the filtered target or null if no element satisfied the selector.
   */
  var filterTarget = function(target, parent) {
    var elem = target,
      className;
    if(target == parent) {
      return null;
    } else {
      do {
        className = ' ' + elem.className + ' ';
        if(elem.nodeType === 1 && className.replace(/[\t\r\n\f]/g, ' ').indexOf('nya-bs-option') >= 0) {
          return elem;
        }
      } while((elem = elem.parentNode) && elem != parent && elem.nodeType !== 9);

      return null;
    }

  };