z.getVars = function (qs, excl_undefined) {
  if (typeof qs === 'undefined') {
    qs = location.search;
  }
  if (qs && qs[0] == '?') {
    qs = qs.substr(1); // Filter off the leading ? if it's there.
  }
  if (!qs) return {};

  return _.chain(qs.split('&')) // ['a=b', 'c=d']
    .map(function (c) {
      return _.map(c.split('='), escape_);
    }) //  [['a', 'b'], ['c', 'd']]
    .filter(function (p) {
      // [['a', 'b'], ['c', undefined]] -> [['a', 'b']]
      return !!p[0] && (!excl_undefined || !_.isUndefined(p[1]));
    })
    .object() // {'a': 'b', 'c': 'd'}
    .value();
};

JSON.parseNonNull = function (text) {
  return JSON.parse(text, function (key, value) {
    if (typeof value === 'object' && value === null) {
      return '';
    }
    return value;
  });
};