code: function addFragmentParam(url, param, value) {
    return url +
        (url.indexOf('#') == -1 ? '#' : '&') +
        encodeURIComponent(param) + '=' + encodeURIComponent(value);
  }
docs: Add a query-like parameter to the fragment string.
  @param {string} url
  @param {string} param
  @param {string} value
  @return {string}