https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/unicode and https://html.spec.whatwg.org/multipage/input.html#the-pattern-attribute The question is how to implement this for UAs, that do not understand the Unicode flag for RegExp’s, notably IE11: https://caniuse.com/mdn-javascript_builtins_regexp_unicode
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/unicode
and
https://html.spec.whatwg.org/multipage/input.html#the-pattern-attribute
The question is how to implement this for UAs, that do not understand the Unicode flag for RegExp’s, notably IE11: https://caniuse.com/mdn-javascript_builtins_regexp_unicode