1. CSS Filter Effects

    Method of applying filter effects using the `filter` property to elements, matching filters available in SVG. Filter functions include blur, brightness, contrast, drop-shadow, grayscale, hue-rotate, invert, opacity, sepia and saturate.

  2. CSS Table display

    Method of displaying elements as tables, rows, and cells. Includes support for all `display: table-*` properties as well as `display: inline-table`

  3. dataset & data-* attributes

    Method of applying and accessing custom data to elements.

  4. Data URIs

    Method of embedding images and other files in webpages as a string of text, generally using base64 encoding.

  5. Decorators

    ECMAScript Decorators are an in-progress proposal for extending JavaScript classes. Decorators use a special syntax, prefixed with an `@` symbol and placed immediately before the code being extended.

  6. DeviceOrientation & DeviceMotion events

    API for detecting orientation and motion events from the device running the browser.

  7. Dialog element

    Method of easily creating custom dialog boxes to display to the user with modal or non-modal options. Also includes a `::backdrop` pseudo-element for behind the element.

  8. EventTarget.dispatchEvent

    Method to programmatically trigger a DOM event.

  9. Do Not Track API

    API to allow the browser's Do Not Track setting to be queried via `navigator.doNotTrack`. Due to lack of adoption the Do Not Track specification was deprecated in 2018.

  10. document.evaluate & XPath

    Allow nodes in an XML/HTML document to be traversed using XPath expressions.

  11. Document Policy

    A mechanism that allows developers to set certain rules and policies for a given site. The rules can change default browser behaviour, block certain features or set limits on resource usage. Document Policy is useful both for security and performance, and is similar to [Permissions Policy](/permissions-policy).

  12. document.scrollingElement

    `document.scrollingElement` refers to the element that scrolls the document.

  13. Document Object Model Range

    A contiguous range of content in a Document, DocumentFragment or Attr

  14. DOMMatrix

    The `DOMMatrix` interface represents 4x4 matrices, suitable for 2D and 3D operations. Supersedes the `WebKitCSSMatrix` and `SVGMatrix` interfaces.

  15. document.elementFromPoint()

    Given coordinates for a point relative to the viewport, returns the element that a click event would be dispatched at if the user were to click the point (in other words, the element that hit-testing would find).

  16. 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`.

  17. display: flow-root

    The element generates a block container box, and lays out its contents using flow layout. It always establishes a new block formatting context for its contents. It provides a better solution to the most use cases of the "clearfix" hack.

  18. Directory selection from file input

    The `webkitdirectory` attribute on the `<input type="file">` element allows entire directory with file contents (and any subdirectories) to be selected.

  19. display: run-in

    If the run-in box contains a block box, same as block. If a block box follows the run-in box, the run-in box becomes the first inline box of the block box. If an inline box follows, the run-in box becomes a block box.

  20. Web SQL Database

    Method of storing data client-side, allows SQLite database queries for access and manipulation.

  21. css property: d

  22. html element: data

  23. html element: del

  24. html element: dfn

  25. html element: dialog

  26. html element: dir

  27. html element: div

  28. html element: dl

  29. html element: dt

  30. javascript built-in: dataview

  31. javascript built-in: date

  32. javascript built-in: date: [symbol.toprimitive]

  33. javascript built-in: date: getmonth

  34. javascript built-in: date: gettime

  35. javascript built-in: date: getyear

  36. javascript built-in: date: now

  37. javascript built-in: date: parse

  38. javascript built-in: date: settime

  39. javascript built-in: date: setyear

  40. javascript built-in: date: tojson

  41. javascript built-in: date: utc

  42. javascript built-in: date: valueof

  43. javascript built-in: disposablestack

  44. javascript built-in: disposablestack: disposablestack

  45. javascript built-in: map: delete

  46. javascript built-in: regexp: dotall

  47. javascript built-in: set: delete

  48. javascript operator: delete

  49. javascript operator: destructuring assignment

  50. javascript statement: debugger