1. CSS Regions

    Method of flowing content into multiple elements, allowing magazine-like layouts. While once supported in WebKit-based browsers and Internet Explorer, implementing the feature is no longer being pursued by any browser.

  2. Lookbehind in JS regular expressions

    The positive lookbehind (`(?<= )`) and negative lookbehind (`(?<! )`) zero-width assertions in JavaScript regular expressions can be used to ensure a pattern is preceded by another pattern.

  3. navigator api: registerprotocolhandler

  4. navigator api: registerprotocolhandler: `scheme` parameter supports `cabal`

  5. navigator api: registerprotocolhandler: `scheme` parameter supports `dat`

  6. navigator api: registerprotocolhandler: `scheme` parameter supports `did`

  7. navigator api: registerprotocolhandler: `scheme` parameter supports `dweb`

  8. navigator api: registerprotocolhandler: `scheme` parameter supports `ftp`

  9. navigator api: registerprotocolhandler: `scheme` parameter supports `ftps`

  10. navigator api: registerprotocolhandler: `scheme` parameter supports `geo`

  11. navigator api: registerprotocolhandler: `scheme` parameter supports `hyper`

  12. navigator api: registerprotocolhandler: `scheme` parameter supports `im`

  13. navigator api: registerprotocolhandler: `scheme` parameter supports `ipfs`

  14. navigator api: registerprotocolhandler: `scheme` parameter supports `ipns`

  15. navigator api: registerprotocolhandler: `scheme` parameter supports `irc`

  16. navigator api: registerprotocolhandler: `scheme` parameter supports `ircs`

  17. navigator api: registerprotocolhandler: `scheme` parameter supports `mms`

  18. navigator api: registerprotocolhandler: `scheme` parameter supports `news`

  19. navigator api: registerprotocolhandler: `scheme` parameter supports `nntp`

  20. navigator api: registerprotocolhandler: `scheme` parameter supports `sftp`

  21. navigator api: registerprotocolhandler: `scheme` parameter supports `sip`

  22. navigator api: registerprotocolhandler: `scheme` parameter supports `sms`

  23. navigator api: registerprotocolhandler: `scheme` parameter supports `ssb`

  24. navigator api: registerprotocolhandler: `scheme` parameter supports `ssh`

  25. navigator api: registerprotocolhandler: `scheme` parameter supports `tel`

  26. navigator api: registerprotocolhandler: `scheme` parameter supports `urn`

  27. navigator api: registerprotocolhandler: `scheme` parameter supports `wtai`

  28. navigator api: registerprotocolhandler: `scheme` parameter supports `xmpp`

  29. navigator api: registerprotocolhandler: secure context required

  30. vttcue api: region

  31. regular_expressions: backreference: `\1`, `\2`

  32. regular_expressions: capturing group: `(...)`

  33. regular_expressions: character class: `[...]`, `[^...]`

  34. regular_expressions: character class escape: `\d`, `\d`, `\w`, `\w`, `\s`, `\s`

  35. regular_expressions: character escape: `\n`, `\x`

  36. regular_expressions: character escape: `\n`, `\x`: unicode character escape: `\u{...}`

  37. regular_expressions: disjunction: `|`

  38. regular_expressions: input boundary assertion: `^`, `$`

  39. regular_expressions: literal character: `a`, `b`

  40. regular_expressions: lookahead assertion: `(?=...)`, `(?!...)`

  41. regular_expressions: lookbehind assertion: `(?<=...)`, `(?<!...)`

  42. regular_expressions: named backreference: `\k<name>`

  43. regular_expressions: named capture group: `(?<name>...)`

  44. regular_expressions: named capture group: `(?<name>...)`: duplicate names in different disjunction alternatives are allowed

  45. regular_expressions: non-capturing group: `(?:...)`

  46. regular_expressions: quantifier: `*`, `+`, `?`, `{n}`, `{n,}`, `{n,m}`

  47. regular_expressions: unicode character class escape: `\p{...}`, `\p{...}`

  48. regular_expressions: wildcard: `.`

  49. regular_expressions: word boundary assertion: `\b`, `\b`

  50. lookahead assertions in js regular expressions