Alternatively: have the element actually do something by hooking it up to the n...

Alternatively: have the element actually do something by hooking it up to the new Moment API and having it display the specified timestamp in the user's locale. That would at least provide an easy way to have the input format and the display format be the same.

But yes, there's also a very good argument to be made in favor of having such localized elements follow the content's `lang` attribute - potentially with a `lang="initial"` to reset it to "whatever the user has configured for their OS".