1. CSS hanging-punctuation

    Allows some punctuation characters from start (or the end) of text elements to be placed "outside" of the box in order to preserve the reading flow.

  2. Media Queries: resolution feature

    Allows a media query to be set based on the device pixels used per CSS unit. While the standard uses `min`/`max-resolution` for this, some browsers support the older non-standard `device-pixel-ratio` media query.

  3. :placeholder-shown CSS pseudo-class

    Input elements can sometimes show placeholder text as a hint to the user on what to type in. See, for example, the placeholder attribute in HTML5. The :placeholder-shown pseudo-class matches an input element that is showing such placeholder text.

  4. CSS grab & grabbing cursors

    Support for the `grab` & `grabbing` values for the `cursor` property. Used to indicate that something can be grabbed (dragged to be moved).

  5. 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.

  6. 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`.

  7. indeterminate checkbox

    Indeterminate checkboxes are displayed in a state which is distinct both from being checked or being unchecked. They are commonly used in hierarchical checkboxes to indicate that only some of the checkbox's descendants are checked.

  8. css property: aspect-ratio

  9. javascript built-in: array: some

  10. javascript built-in: iterator: some

  11. javascript built-in: typedarray: some