If you work with temporal data on the web then you may be interested in a couple of proposals currently going through the specifications bodies. In the next few years we could see an extension to the venerable ISO8601 specification and even a new temporal API for JavaScript.

ISO 8601 and EDTF

There are many standards for encoding temporal data but the vast majority of these have been derived from ISO8601. The specification offers a variety of encoding options so it's rare to see an implementation of all of it. What most often happens is another standard adopts a stricter subset of ISO8601 rules, known as a "profile", and this is what is implemented in the wild.

The ISO8601 specification has been tightened up a bit over the years but very little has really changed. At the moment however the ISO committee are considering the first ever extension to the specification. I've been tracking a project called EDTF for a number of years. The Extended Date Time Format was developed by the Library of Congress to produce a reasonably comprehensive date/time definition for the bibliographic community. This project is currently before ISO and awaiting approval as an extension to ISO8601.

JavaScript

A few days ago I came across a talk by Matt Johnson from JSConf EU 2017. In it he covers why the current Date Object is not fit for purpose. Many of us have been down this road but it seems at last there is hope. Matt mentions a stage 1 TC39 committee with the general approval to explore a new Date API for JavaScript. Maggie Pint is representing the JavaScript Foundation on the committee. If you want to get involved you can find more information on her GitHub.