Earlier quoted context omitted.
> a good interface will accept leading, trailing, or interior spaces Won't pattern="[0-9]*" do the exact opposite of what you're suggesting?
Yes, you're right, this isn't a great solution for credit card inputs either. They should be able handle dashes and other spacing characters and the site should be able to filter/format it automatically either on the front-end before submission or with some server-side processing. And no we don't need four different input boxes to enter a credit card numbers either. Flexibility is key here and since many websites han…
I feel most of these things should be solved by browsers, not designers...
Problem is for something like credit card every single browser vendor will try to plug their own service in one way or another (think Apple Pay and Android Pay).