[1] Selectors API Level 1 ( (2/21/2013, 5:57:52 PM 版)) <http://www.w3.org/TR/2013/REC-selectors-api-20130221/>

[2] Align with changes in Selectors ( (annevk著, 6/10/2016, 7:44:08 AM)) <https://github.com/whatwg/dom/commit/1594aa52357371354780750413ad88e9e8a2b56b>