34. :nth-of-type
select multiple elements according to their
position in the document tree BUT only those
elements that are the same as the type the rule is
applied to.
97. WHAT IS A POLYFILL?
A polyfill, or polyfiller, is a piece of code (or
plugin) that provides the technology that you, the
developer, expect the browser to provide natively.
http://remysharp.com/2010/10/08/what-is-a-polyfill/