Allowing return fractional as well as integral bits (for submillisecond timing)

Paul Biggar pbiggar at
Fri Aug 6 13:27:34 PDT 2010


In SpiderMonkey, we can very easily make return fractional
bits, which allows sub-millisecond timing. I've been using this for a
few weeks, and it's been very useful for my small purposes (more
accurate benchmarks). We're now looking at making this a feature of

According to Brendan's reading of the standard, this is allowed,
partially due to being underspecified. The question is
whether this is a good idea, or if we should shelve it pending the
nanoAge proposal, or propose a
Date.nowWithFractionalBitsAndABetterName() instead?

The Mozilla bug is here:

Comments appreciated.


Paul Biggar
Javascript core engineer
pbiggar at

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