1. ChildNode.remove()

    DOM node method to remove the node itself from the document.

  2. CSS display: contents

    `display: contents` causes an element's children to appear as if they were direct children of the element's parent, ignoring the element itself. This can be useful when a wrapper element should be ignored when using CSS grid or similar layout techniques.

  3. :has() CSS relational pseudo-class

    Select elements containing specific content. For example, `a:has(img)` selects all `<a>` elements that contain an `<img>` child.

  4. CSS Nesting

    CSS nesting provides the ability to nest one style rule inside another, with the selector of the child rule relative to the selector of the parent rule. Similar behavior previously required a CSS pre-processor.

  5. selector list argument of :nth-child and :nth-last-child CSS pseudo-classes

    The newest versions of `:nth-child()` and `:nth-last-child()` accept an optional `of S` clause which filters the children to only those which match the selector list `S`. For example, `:nth-child(1 of .foo)` selects the first child among the children that have the `foo` class (ignoring any non-`foo` children which precede that child). Similar to `:nth-of-type`, but for arbitrary selectors instead of only type selectors.

  6. CSS 2.1 selectors

    Basic CSS selectors including: `*` (universal selector), `>` (child selector), `:first-child`, `:link`, `:visited`, `:active`, `:hover`, `:focus`, `:lang()`, `+` (adjacent sibling selector), `[attr]`, `[attr="val"]`, `[attr~="val"]`, `[attr|="bar"]`, `.foo` (class selector), `#foo` (id selector)

  7. CSS3 selectors

    Advanced element selection using selectors including: `[foo^="bar"]`, `[foo$="bar"]`, `[foo*="bar"]`, `:root`, `:nth-child()`, `:nth-last-child()`, `:nth-of-type()`, `:nth-last-of-type()`, `:last-child`, `:first-of-type`, `:last-of-type`, `:only-child`, `:only-of-type`, `:empty`, `:target`, `:enabled`, `:disabled`, `:checked`, `:not()`, `~` (general sibling)

  8. Details & Summary elements

    The <details> element generates a simple no-JavaScript widget to show/hide element contents, optionally by clicking on its child <summary> element.

  9. 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`.

  10. Element.insertAdjacentElement() & Element.insertAdjacentText()

    Methods for inserting an element or text before or after a given element, or appending or prepending an element or text to a given element's list of children.

  11. documentfragment api: childelementcount

  12. documentfragment api: children

  13. documentfragment api: firstelementchild

  14. documentfragment api: lastelementchild

  15. documentfragment api: replacechildren

  16. document api: childelementcount

  17. document api: children

  18. document api: firstelementchild

  19. document api: lastelementchild

  20. document api: replacechildren

  21. element api: childelementcount

  22. element api: children

  23. element api: firstelementchild

  24. element api: lastelementchild

  25. element api: replacechildren

  26. node api: appendchild

  27. node api: childnodes

  28. node api: firstchild

  29. node api: haschildnodes

  30. node api: lastchild

  31. node api: removechild

  32. node api: replacechild

  33. notrestoredreasons api: children

  34. selection api: selectallchildren

  35. treewalker api: firstchild

  36. treewalker api: lastchild

  37. css property: position: absolutely-positioned flex children

  38. css selector: child combinator (`a > b`)

  39. css selector: `:first-child`

  40. css selector: `:first-child`: matches elements with no parent

  41. css selector: `:last-child`

  42. css selector: `:last-child`: matches elements with no parent

  43. css selector: `:nth-child()`

  44. css selector: `:nth-child()`: matches elements with no parent

  45. css selector: `:nth-last-child()`

  46. css selector: `:nth-last-child()`: matches elements with no parent

  47. css selector: `:nth-last-child()`: `of <selector>` syntax

  48. css selector: `:only-child`

  49. css selector: `:only-child`: matches elements with no parent

  50. headers http header: content-security-policy: child-src