1. CSS font-stretch

    If a font has multiple types of variations based on the width of characters, the `font-stretch` property allows the appropriate one to be selected. The property in itself does not cause the browser to stretch to a font.

  2. letter-spacing CSS property

    Controls spacing between characters of text (i.e. "tracking" in typographical terms). Not to be confused with kerning.

  3. Minimum length attribute for input fields

    Declares a lower bound on the number of characters a user can input.

  4. KeyboardEvent.key

    A `KeyboardEvent` property whose value is a string identifying the key that was pressed. Covers character keys, non-character keys (e.g. arrow keys), and dead keys.

  5. maxlength attribute for input and textarea elements

    Declares an upper bound on the number of characters the user can input. Normally the UI ignores attempts by the user to type in additional characters beyond this limit.

  6. Mutation events

    Deprecated mechanism for listening to changes made to the DOM, replaced by Mutation Observers.

  7. ES6 Template Literals (Template Strings)

    Template literals are string literals allowing embedded expressions using backtick characters (`). You can use multi-line strings and string interpolation features with them. Formerly known as template strings.

  8. bluetoothcharacteristicproperties api: writewithoutresponse

  9. bluetoothremotegattcharacteristic api: writevaluewithoutresponse

  10. characterdata api: substringdata

  11. svgtextcontentelement api: getrotationofchar

  12. css property: text-transform: greek accented letters

  13. types: <string>: unicode escaped characters (`\xx`)

  14. html element: tr: char

  15. html element: tr: charoff

  16. javascript built-in: string: charat

  17. javascript built-in: string: charcodeat

  18. javascript built-in: string: fromcharcode