October 2017 web platform update

Newly available on the web platform
Newly available

<time>: The <time> HTML element represents a time, such as a calendar date, clock time, or duration. It may include the datetime attribute to translate dates into machine-readable format. Learn more.
Viewport units: The vw, vh, vmin, and vmax CSS viewport units are relative to the size of the viewport, and are used to size elements in relation to the viewport's dimensions. Learn more.

Abortable fetch: If you construct a fetch request with an AbortSignal, you can cancel the request. Learn more.
AbortController and AbortSignal: The AbortController and AbortSignal APIs allow you to cancel an ongoing operation, such as a fetch() request. Learn more.
Intersection observer: The Intersection Observer API asynchronously observes changes in the intersection of a target element with an ancestor element or with a top-level document's viewport. Learn more.
JavaScript modules: JavaScript modules allow code to be organized into reusable units. Modules use import to load other modules and export to declare what is available to import from other modules. In HTML, modules are loaded with <script type="module">. 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.