Form validation: the checks every sign-up and checkout relies on

Form validation now works the way it does in every mainstream browser, so the sign-up, checkout and contact forms that real sites ship behave correctly. The engine understands a form's own rules: a required field left empty, an email or web-address field holding something that is not one, a field that must match a pattern or stay within a length or a number range, are all recognized as invalid, with the same messages browsers show. A page's script can ask a single field or a whole form whether it is valid, set its own custom error message, and have the form refuse to submit until everything is correct, exactly as the standard describes. And pages can style their fields on validity: the rules that turn a bad field red or a good one green now match the field's real state and update as you type, because the styling and the script read from one shared validity check instead of disagreeing. This is a general capability that lifts every form on the web; pages without form validation are unchanged. It moves the overall platform score to 68.