1. Brotli Accept-Encoding/Content-Encoding

    More effective lossless compression algorithm than gzip and deflate.

  2. Web Cryptography

    JavaScript API for performing basic cryptographic operations in web applications

  3. :optional CSS pseudo-class

    The `:optional` pseudo-class matches form inputs (`<input>`, `<textarea>`, `<select>`) which are not `:required`.

  4. Encrypted Media Extensions

    The EncryptedMediaExtenstions API provides interfaces for controlling the playback of content which is subject to a DRM scheme.

  5. ECMAScript 5

    Full support for the ECMAScript 5 specification. Features include `Function.prototype.bind`, Array methods like `indexOf`, `forEach`, `map` & `filter`, Object methods like `defineProperty`, `create` & `keys`, the `trim` method on Strings and many more.

  6. ECMAScript 2015 (ES6)

    Support for the ECMAScript 2015 specification. Features include Promises, Modules, Classes, Template Literals, Arrow Functions, Let and Const, Default Parameters, Generators, Destructuring Assignment, Rest & Spread, Map/Set & WeakMap/WeakSet and many more.

  7. JavaScript modules: dynamic import()

    Loading JavaScript modules dynamically using the import() syntax

  8. HTML Media Capture

    Facilitates user access to a device's media capture mechanism, such as a camera, or microphone, from within a file upload control.

  9. ImageCapture API

    The Image Capture API provides access to the Video Camera for taking photos while configuring picture-specific settings such as e.g. zoom or auto focus metering area.

  10. Media Capture from DOM Elements API

    API to capture Real-Time video and audio from a DOM element, such as a `<video>`, `<audio>`, or `<canvas>` element via the `captureStream` method, in the form of a `MediaStream`

  11. async attribute for external scripts

    The boolean async attribute on script elements allows the external JavaScript file to run when it's available, without delaying page load first.

  12. defer attribute for external scripts

    The boolean defer attribute on script elements allows the external JavaScript file to run when the DOM is loaded, without delaying page load first.

  13. SDCH Accept-Encoding/Content-Encoding

    Shared Dictionary Compression over HTTP

  14. X-Frame-Options HTTP header

    An HTTP header which indicates whether the browser should allow the webpage to be displayed in a frame within another webpage. Used as a defense against clickjacking attacks.

  15. css api: `pt()` static method

  16. javascript built-in: asyncdisposablestack: adopt

  17. javascript built-in: disposablestack: adopt

  18. javascript built-in: intl: collator: resolvedoptions

  19. javascript built-in: intl: datetimeformat: resolvedoptions

  20. javascript built-in: intl: datetimeformat: resolvedoptions: computed `timezone`

  21. javascript built-in: intl: displaynames: resolvedoptions

  22. javascript built-in: intl: durationformat: resolvedoptions

  23. javascript built-in: intl: listformat: resolvedoptions

  24. javascript built-in: intl: locale: script

  25. javascript built-in: intl: numberformat: `numberformat()` constructor: `options` parameter: `options.currencydisplay` parameter

  26. javascript built-in: intl: numberformat: `numberformat()` constructor: `options` parameter: `options.currencysign` parameter

  27. javascript built-in: intl: numberformat: `numberformat()` constructor: `options` parameter: `options.currency` parameter

  28. javascript built-in: intl: numberformat: `numberformat()` constructor: `options` parameter: `options.maximumfractiondigits` parameter

  29. javascript built-in: intl: numberformat: `numberformat()` constructor: `options` parameter: `options.minimumfractiondigits` parameter

  30. javascript built-in: intl: numberformat: `numberformat()` constructor: `options` parameter: `options.minimumintegerdigits` parameter

  31. javascript built-in: intl: numberformat: `numberformat()` constructor: `options` parameter: `options.roundingincrement` parameter

  32. javascript built-in: intl: numberformat: `numberformat()` constructor: `options` parameter: `options.roundingmode` parameter

  33. javascript built-in: intl: numberformat: `numberformat()` constructor: `options` parameter: `options.roundingpriority` parameter

  34. javascript built-in: intl: numberformat: `numberformat()` constructor: `options` parameter: `options.style` parameter

  35. javascript built-in: intl: numberformat: `numberformat()` constructor: `options` parameter: `options.trailingzerodisplay` parameter

  36. javascript built-in: intl: numberformat: `numberformat()` constructor: `options` parameter: `options.unitdisplay` parameter

  37. javascript built-in: intl: numberformat: `numberformat()` constructor: `options` parameter: `options.unit` parameter

  38. javascript built-in: intl: numberformat: resolvedoptions

  39. javascript built-in: intl: pluralrules: `pluralrules()` constructor: `options` parameter: `options.roundingincrement` parameter

  40. javascript built-in: intl: pluralrules: `pluralrules()` constructor: `options` parameter: `options.roundingmode` parameter

  41. javascript built-in: intl: pluralrules: `pluralrules()` constructor: `options` parameter: `options.roundingpriority` parameter

  42. javascript built-in: intl: pluralrules: `pluralrules()` constructor: `options` parameter: `options.trailingzerodisplay` parameter

  43. javascript built-in: intl: pluralrules: resolvedoptions

  44. javascript built-in: intl: relativetimeformat: resolvedoptions

  45. javascript built-in: intl: segmenter: resolvedoptions

  46. javascript built-in: object: getownpropertydescriptor

  47. javascript built-in: object: getownpropertydescriptors

  48. javascript built-in: reflect: getownpropertydescriptor

  49. javascript built-in: symbol: description

  50. javascript statement: empty statement (`;`)