Browsers which support HTML5 form validation are "suppose," to validate the input prior to submitting the forms. I think this trended a bit ago here on HN about email validation...even if you do a <input type="email">, a user can still submit an email in these forms (blah@you , 123@12.zz , 12345@localhost ,...get the idea).
Another quirk about form validation in HTML5 is the forms won't get validated UNTIL the user submits the form and then the browser may highlight the error in consecutive order (1 at a time o_O), imagine your poor UX for a user that has multiple errors.
Another quirk about form validation in HTML5 is the forms won't get validated UNTIL the user submits the form and then the browser may highlight the error in consecutive order (1 at a time o_O), imagine your poor UX for a user that has multiple errors.