1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Efficient Script Yielding: setImmediate()

    Yields control flow without the minimum delays enforced by setTimeout

  6. document api: scripts

  7. performancelonganimationframetiming api: scripts

  8. scriptprocessornode api

  9. scriptprocessornode api: `audioprocess` event

  10. scriptprocessornode api: buffersize

  11. serviceworker api: scripturl

  12. html element: script

  13. html element: script: attributionsrc

  14. html element: script: blocking

  15. html element: script: crossorigin

  16. html element: script: fetchpriority

  17. html element: script: integrity

  18. html element: script: nomodule

  19. html element: script: referrerpolicy

  20. html element: script: referrerpolicy: no-referrer-when-downgrade

  21. html element: script: referrerpolicy: origin-when-cross-origin

  22. html element: script: referrerpolicy: unsafe-url

  23. html element: script: src

  24. html element: script: type

  25. html element: script: type: `type="importmap"`

  26. html element: script: type: `type="module"`

  27. html element: script: type: `type="speculationrules"`

  28. html element: script: type: `type="speculationrules"`: `eagerness` key

  29. html element: script: type: `type="speculationrules"`: `expects_no_vary_search` key

  30. html element: script: type: `type="speculationrules"`: `prefetch` key

  31. html element: script: type: `type="speculationrules"`: `prerender` key

  32. html element: script: type: `type="speculationrules"`: `referrer_policy` key

  33. html element: script: type: `type="speculationrules"`: `relative_to` key

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

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

  36. html element: script: type: `type="speculationrules"`: `source` key is optional

  37. html element: script: type: `type="speculationrules"`: `urls` key

  38. html element: script: type: `type="speculationrules"`: `where` key

  39. headers http header: content-security-policy: script-src

  40. headers http header: content-security-policy: script-src-attr

  41. headers http header: content-security-policy: script-src-elem

  42. headers http header: content-security-policy: script-src: external scripts with hash

  43. headers http header: content-security-policy: script-src: `inline-speculation-rules` source expression

  44. headers http header: content-security-policy: script-src: source expression allowing webassembly execution

  45. svg element: script

  46. svg element: script: async

  47. svg element: script: defer

  48. svg element: script: type

  49. svg element: script: type: `type='module'`

  50. svg element: script: xlink:href