1. HTML5 semantic elements

    HTML5 offers some new elements, primarily for semantic purposes. The elements include: `section`, `article`, `aside`, `header`, `footer`, `nav`, `figure`, `figcaption`, `time`, `mark` & `main`.

  2. IntersectionObserver

    API that can be used to understand the visibility and position of DOM elements relative to a containing element or to the top-level viewport. The position is delivered asynchronously and is useful for understanding the visibility of elements and implementing pre-loading and deferred loading of DOM content.

  3. IntersectionObserver V2

    Iteration on the original API that also reports if the element is covered by another element or has filters applied to it. Useful for blocking clickjacking attempts or tracking ad exposure.

  4. cdatasection api

  5. document api: createcdatasection

  6. htmltablerowelement api: sectionrowindex

  7. htmltablesectionelement api

  8. htmltablesectionelement api: align

  9. htmltablesectionelement api: ch

  10. htmltablesectionelement api: choff

  11. htmltablesectionelement api: deleterow

  12. htmltablesectionelement api: insertrow

  13. htmltablesectionelement api: rows

  14. htmltablesectionelement api: valign

  15. intersectionobserver api

  16. intersectionobserverentry api

  17. intersectionobserverentry api: boundingclientrect

  18. intersectionobserverentry api: `intersectionobserverentry()` constructor

  19. intersectionobserverentry api: intersectionratio

  20. intersectionobserverentry api: intersectionrect

  21. intersectionobserverentry api: isintersecting

  22. intersectionobserverentry api: isvisible

  23. intersectionobserverentry api: rootbounds

  24. intersectionobserverentry api: target

  25. intersectionobserverentry api: time

  26. intersectionobserver api: delay

  27. intersectionobserver api: disconnect

  28. intersectionobserver api: `intersectionobserver()` constructor

  29. intersectionobserver api: `intersectionobserver()` constructor: `options.root` parameter can be a `document`

  30. intersectionobserver api: `intersectionobserver()` constructor: `options.trackvisibility` parameter

  31. intersectionobserver api: observe

  32. intersectionobserver api: root

  33. intersectionobserver api: rootmargin

  34. intersectionobserver api: scrollmargin

  35. intersectionobserver api: takerecords

  36. intersectionobserver api: thresholds

  37. intersectionobserver api: trackvisibility

  38. intersectionobserver api: unobserve

  39. performancecontainertiming api: intersectionrect

  40. performanceelementtiming api: intersectionrect

  41. svgsvgelement api: checkintersection

  42. svgsvgelement api: getintersectionlist

  43. css property: row-rule-break: intersection

  44. css property: rule-break: intersection

  45. html element: h1: no user agent styles in `<article>`, `<aside>`, `<nav>`, and `<section>`.

  46. html element: section

  47. javascript built-in: set: intersection

  48. api: module: `customsections()` static method

  49. definitions: import: compact import section