September 2019 web platform update

Now widely available on the web platform
Widely available

Classes: Classes are an object-oriented syntax for JavaScript prototypes. Learn more.
Clipboard events: The "copy", "cut", and "paste" events fire on elements when the user starts an action with the clipboard. Learn more.
Fetch: The fetch() method makes asynchronous HTTP requests. Learn more.

Intl.PluralRules: The Intl.PluralRules API creates a locale-aware object that tells you which of the language's pluralization rules apply based on a given number. Learn more.
Print events: An alternative to @media print queries, the beforeprint and afterprint events allow you to change the page for printing and and restore the page after printing. Learn more.
Sticky positioning: The position: sticky CSS declaration positions an element in the normal flow until it crosses a specified threshold, at which points it becomes fixed (stuck) at that position. Learn more.