1. Printing Events

    Window fires `beforeprint` and `afterprint` events so the printed document can be annotated.

  2. CSS Generated content for pseudo-elements

    Method of displaying text or images before or after the given element's contents using the ::before and ::after pseudo-elements. All browsers with support also support the `attr()` notation in the `content` property.

  3. DOM manipulation convenience methods

    jQuery-like methods on DOM nodes to insert nodes around or within a node, or to replace one node with another. These methods accept any number of DOM nodes or HTML strings as arguments. Includes: `ChildNode.before`, `ChildNode.after`, `ChildNode.replaceWith`, `ParentNode.prepend`, and `ParentNode.append`.

  4. beforeinstallpromptevent api

  5. beforeinstallpromptevent api: `beforeinstallpromptevent()` constructor

  6. beforeinstallpromptevent api: platforms

  7. beforeinstallpromptevent api: prompt

  8. beforeinstallpromptevent api: userchoice

  9. beforeunloadevent api

  10. beforeunloadevent api: returnvalue

  11. beforeunloadevent api: user interaction required for dialog box

  12. characterdata api: before

  13. documenttype api: before

  14. document api: `beforescriptexecute` event

  15. element api: before

  16. element api: `beforeinput` event

  17. element api: `beforematch` event

  18. element api: `beforescriptexecute` event

  19. element api: `beforexrselect` event

  20. htmlelement api: `beforetoggle` event

  21. window api: `beforeinstallprompt` event

  22. window api: `beforeprint` event

  23. window api: `beforeunload` event

  24. window api: `beforeunload` event: activation by setting `event.returnvalue` to any truthy value

  25. window api: `beforeunload` event: dialog displays a generic string, not event handler return value

  26. window api: `beforeunload` event: activation using `event.preventdefault()`

  27. window api: `beforeunload` event: activation by returning a string

  28. css property: break-before

  29. css property: break-before: always

  30. css property: break-before: auto

  31. css property: break-before: avoid

  32. css property: break-before: avoid-column

  33. css property: break-before: avoid-page

  34. css property: break-before: column

  35. css property: break-before: left

  36. css property: break-before: supported in multi-column layout

  37. css property: break-before: supported in multi-column layout: `always`

  38. css property: break-before: supported in multi-column layout: `avoid`

  39. css property: break-before: supported in multi-column layout: `avoid-column`

  40. css property: break-before: supported in multi-column layout: `column`

  41. css property: break-before: page

  42. css property: break-before: supported in paged media

  43. css property: break-before: supported in paged media: `always`

  44. css property: break-before: supported in paged media: `page` and `avoid-page`

  45. css property: break-before: supported in paged media: `recto` and `verso`

  46. css property: break-before: recto

  47. css property: break-before: right

  48. css property: break-before: verso

  49. css property: page-break-before

  50. css selector: `::before`: animation and transition support