Real World Haskell の HTML 中に節番号振るグリモン

section_numbers_for_real_world_haskell.user.js

// ==UserScript==
// @name           section_numbers_for_real_world_haskell.user.js
// @namespace      http://yuyat.jp/
// @description    Gives section numbers for Real World Haskell book online.
// @include        http://book.realworldhaskell.org/read/*
// ==/UserScript==

(function (elements) {
  var n = 1;
  for (var i in elements) {
    var element = elements[i];
    if (i > 0 && element.tagName === 'H2') {
      element.innerHTML = n + ". " + element.innerHTML;
      n += 1;
    }
  }
})(document.getElementsByClassName('title'));