[javascript] Get Locale Short Date Format using javascript

If your question about <input type="date"> field, here is script for getting filed value="" attribute:

(new Date()).toISOString().split('T')[0]

You can use the Intl object (ecma-402) to get data-date-pattern="":

(new Intl.DateTimeFormat()).resolved.pattern // "M/d/y" for "en-US" in Google Chrome

And finnaly, to format date in current l10n, data-date="":

(new Intl.DateTimeFormat()).format(new Date());

Polyfill: https://github.com/andyearnshaw/Intl.js/issues/129