Find words in a class or any HTML attribute by regex
https://stackoverflow.com/questions/22298358/find-class-name-by-regex
class=/(.*[\s+\"\']btn[\s+\"\'].*)/g
Find CSS Comments
https://projects.lukehaas.me/regexhub/
/\/\*[^*]*\*+([^\/*][^*]*\*+)*\//