The connectEnd property returns the timestamp immediately after the browser finishes establishing the connection to the server to retrieve the resource. The timestamp value includes the time interval to establish the transport connection, as well as other time intervals such as SSL handshake and SOCKS authentication.
The decodedBodySize property returns the size (in octets) received from the fetch (HTTP or cache) of the message body, after removing any applied content-codings. If the resource is retrieved from an application cache or local resources, it returns the size of the payload after removing any applied content-codings.
The requestStart property returns a timestamp of the time immediately before the browser starts requesting the resource from the server, cache, or local resource. If the transport connection fails and the browser retires the request, the value returned will be the start of the retry request.
The secureConnectionStart property returns a timestamp immediately before the browser starts the handshake process to secure the current connection. If a secure connection is not used, the property returns zero.
If the current context is a worker, the workerStart property returns a timestamp immediately before the worker that fetches the resource is started. If the context is not a worker (i.e. a browser context), this property returns zero.
The High Resolution Time standard defines a Performance interface that supports client-side latency measurements within applications. The Performance interfaces are considered high resolution because they are accurate to a thousandth of a millisecond (subject to hardware or software constraints). The interfaces support a number of use cases including calculating frame-rates (potentially important in animations) and benchmarking (such as the time to load a resource).