CSS Pseudoelement in Tag definieren

[suit]

“2009-06 HTML5 Candidate Recommendation
2010-06 HTML5 Proposed Recommendation
2010-09 HTML5 Recommendation” [http://www.w3.org/html/wg/]

Um deren eigene Prognose zu vervollständigen:
"2018-07 HTML5 widespread [1] browsersupport
[1] 75% market share"