[1] Selectors API Level 1 ( (2013-02-22 02:57:52 +09:00 版)) <http://www.w3.org/TR/2013/REC-selectors-api-20130221/>

[2] Align with changes in Selectors ( (annevk著, 2016-06-10 16:44:08 +09:00)) <https://github.com/whatwg/dom/commit/1594aa52357371354780750413ad88e9e8a2b56b>