The CSSKeyframeRule interface describes an object representing a set of style for a given keyframe. It corresponds to the contains of a single keyframe of a @keyframesat-rule. It implements the CSSRule interface with a type value of 8 (CSSRule.KEYFRAME_RULE).
The CSSKeyframesRule interface describes an object representing a complete set of keyframes for a CSS animation. It corresponds to the contains of a whole @keyframesat-rule. It implements the CSSRule interface with a type value of 7 (CSSRule.KEYFRAMES_RULE).
A DOMCursor object represents an ongoing operation over a list of results. It is an enhanced DOMRequest that allows to iterate through a list of results asynchronously. Each time its continue() method is called, the DOMCursor tries to reach the next result in the list and calls its result's success or error accordingly.
A DOMRequest object represents an ongoing operation. It provides callbacks that are called when the operation completes, as well as a reference to the operation's result. A DOM method that initiates an ongoing operation may return a DOMRequest object that you can use to monitor the progress of that operation.
The ExtendableMessageEvent interface of the ServiceWorker API represents the event object of a message event fired on a service worker (when a channel message is received on the ServiceWorkerGlobalScope from another context) — extends the lifetime of such events.