On Wed, Jan 04, 2017 at 09:49:35AM +0100, Harald Alvestrand wrote: > FWIW, the W3C has switched to defining time inside a Web page in two > segments: > - Page load time, which is UTC-derived (POSIX time extended to > milliseconds), and can jump when the system clock is reset > - Events related to the page load time, which has floating-point > representation, and is guaranteed to be monotonic. But aren't these relative times (intervals)? As long as they are short enough, distinctions between UTC, TAI, local, and smeared time will make little difference most of the time. (Naturally, using local time might cause a page load time to appear to be negative, or over an hour, around daylight savings switch overs, or if one is moving across timezones, thus "most of the time".)