1. Crisp edges/pixelated images

    Scales images with an algorithm that preserves edges and contrast, without smoothing colors or introducing blur. This is intended for images such as pixel art. Official values that accomplish this for the `image-rendering` property are `crisp-edges` and `pixelated`.

  2. :is() CSS pseudo-class

    The `:is()` (formerly `:matches()`, formerly `:any()`) pseudo-class checks whether the element at its position in the outer selector matches any of the selectors in its selector list. It's useful syntactic sugar that allows you to avoid writing out all the combinations manually as separate selectors. The effect is similar to nesting in Sass and most other CSS preprocessors.

  3. CSS Flexible Box Layout Module

    Method of positioning elements in horizontal or vertical stacks. Support includes all properties prefixed with `flex`, as well as `display: flex`, `display: inline-flex`, `align-content`, `align-items`, `align-self`, `justify-content` and `order`.

  4. Permissions API

    High-level JavaScript API for checking and requesting permissions

  5. event api: istrusted

  6. external api: issearchproviderinstalled

  7. idbindex api: isautolocale

  8. issecurecontext api

  9. issecurecontext api: available in workers

  10. node api: isconnected

  11. node api: isdefaultnamespace

  12. node api: isequalnode

  13. node api: issamenode

  14. origin api: issameorigin

  15. origin api: issamesite

  16. range api: ispointinrange

  17. request api: isreloadnavigation

  18. screen api: isextended

  19. selection api: iscollapsed

  20. usbdevice api: isochronoustransferin

  21. usbdevice api: isochronoustransferout

  22. xrsession api: issystemkeyboardsupported

  23. xrview api: isfirstpersonobserver

  24. javascript built-in: arraybuffer: isview

  25. javascript built-in: array: isarray

  26. javascript built-in: atomics: islockfree

  27. javascript built-in: error: iserror

  28. javascript built-in: isfinite

  29. javascript built-in: isnan

  30. javascript built-in: json: israwjson

  31. javascript built-in: number: isfinite

  32. javascript built-in: number: isinteger

  33. javascript built-in: number: isnan

  34. javascript built-in: number: issafeinteger

  35. javascript built-in: object: is

  36. javascript built-in: object: isextensible

  37. javascript built-in: object: isfrozen

  38. javascript built-in: object: isprototypeof

  39. javascript built-in: object: issealed

  40. javascript built-in: proxy: handler: isextensible

  41. javascript built-in: reflect: isextensible

  42. javascript built-in: set: issubsetof

  43. javascript built-in: set: issupersetof

  44. javascript built-in: string: iswellformed

  45. javascript built-in: symbol: isconcatspreadable