var arr = ['a14', 'a167', 'a25', 'a34', 'a210'];
arr.sort(
  function (a, b) {
    if (typeof a === 'string' && typeof b === 'string') {
      return parseInt(a.replace(/\D/, '')) - parseInt(b.replace(/\D/, ''));
    } else {
      return a > b ? 1 : -1;
    }
  }
);
alert(arr.join(','));