Er, why doesn’t HTML5 just use ISO 8601?

Why the HELL have they gone and invented their own datetime specification?

Several reasons:

• ISO8601 does not define how to handle invalid strings for example
• ISO8601 actually allows three different forms for the date

Thanks to #whatwg guys for informing me. Again.

• Background HTML5 ’time date’ discussion on IRC

The same reasoning could be applied to XSD dates.