Form Validation Using JavaScript's Constraint Validation API (blog.openreplay.com)

This is great. One issue: type url requires "https://".

I recently got locked out of a site because they screwed up validation. I used a gmail alias to sign up, my.mail+thesite@gmail.com, couldn't submit, couldn't trick it to submit anyway because who uses a real submit these days... I went there to cancel a subscription, decided it was easier to block them from taking the money than to contact support.