1. Audio element

    Method of playing sound on webpages (without requiring a plug-in). Includes support for the following media properties: `currentSrc`, `currentTime`, `paused`, `playbackRate`, `buffered`, `duration`, `played`, `seekable`, `ended`, `autoplay`, `loop`, `controls`, `volume` & `muted`

  2. Media Queries: interaction media features

    Allows a media query to be set based on the presence and accuracy of the user's pointing device, and whether they have the ability to hover over elements on the page. This includes the `pointer`, `any-pointer`, `hover`, and `any-hover` media features.

  3. Picture element

    A responsive images method to control which image resource a user agent presents to a user, based on resolution, media query and/or support for a particular image format

  4. querySelector/querySelectorAll

    Method of accessing DOM elements using CSS selectors

  5. Video element

    Method of playing videos on webpages (without requiring a plug-in). Includes support for the following media properties: `currentSrc`, `currentTime`, `paused`, `playbackRate`, `buffered`, `duration`, `played`, `seekable`, `ended`, `autoplay`, `loop`, `controls`, `volume` & `muted`

  6. elementinternals api: ariarequired

  7. element api: ariarequired

  8. element api: getboxquads

  9. element api: queryselector

  10. element api: queryselectorall

  11. element api: requestfullscreen

  12. element api: requestfullscreen: `options.navigationui` parameter

  13. element api: requestfullscreen: `options.screen` parameter

  14. element api: requestfullscreen: returns a `promise`

  15. element api: requestpointerlock

  16. element api: requestpointerlock: `options.unadjustedmovement` parameter

  17. htmlcanvaselement api: toblob: `quality` parameter

  18. htmlmarqueeelement api

  19. htmlquoteelement api

  20. htmlquoteelement api: cite

  21. html element: blockquote

  22. html element: blockquote: cite

  23. html element: canvas: moz-opaque

  24. html element: html: manifest: secure context required

  25. html element: iframe: allowpaymentrequest

  26. html element: marquee

  27. html element: marquee: behavior

  28. html element: marquee: bgcolor

  29. html element: marquee: direction

  30. html element: marquee: height

  31. html element: marquee: hspace

  32. html element: marquee: loop

  33. html element: marquee: scrollamount

  34. html element: marquee: scrolldelay

  35. html element: marquee: truespeed

  36. html element: marquee: vspace

  37. html element: marquee: width

  38. html element: meta: http-equiv

  39. html element: meta: http-equiv: content-language

  40. html element: meta: http-equiv: content-security-policy

  41. html element: meta: http-equiv: content-type

  42. html element: meta: http-equiv: refresh

  43. html element: meta: http-equiv: set-cookie

  44. html element: q

  45. html element: q: cite

  46. html element: script: type: `type="speculationrules"`: `requires` key

  47. html element: script: type: `type="speculationrules"`: `requires` key: `anonymous-client-ip-when-cross-origin` value

  48. html element: select: required

  49. html element: textarea: required

  50. svg element: feturbulence: basefrequency