New answers tagged validation
First thing I found - firstname.lastname@example.org doesn't exist - but email@example.com does actually exist so it's not so silly an email. This got a bit long, so tl;dr Pinterest - liars Google, Facebook, Trello (nicely) - all tell you if the account exists Slack - agree with you and gurvinder372's answer Personally I'm a fan of Slack's UX in general, you could also ...
Three points you should consider 1) They didn't lied to the customer. Customer gave an email address to recover a password with which he has never registered. So, customer lied first (this is why email confirmation field is present most of the times during registration). 2) It is not secure to tell the user that firstname.lastname@example.org doesn't exist, since then an ...
Your idea is a good one: in situations where you have a hard requirement on an input, make it impossible for the user to make a mistake. I've used a combination approach to good effect. If the user presses a key for a disallowed character: Prevent the character from being added Display a message, clearly tied to the field ("Oops, please enter numbers ...
I have something similar which I implemented for phone entry. I added an event tracking to monitor the bounce rate for this particular field. So far the usability has been pretty ok. I suppose you could extend this to include other characters like +, - or floating points. download bmml source – Wireframes created with Balsamiq Mockups
If you want to avoid confusion, you could display an error message below the entry box (or someplace else) that they tried to add an illegal character. This is preferable to letting them enter illegal characters, which would lead to more problems and them wasting effort on having to reenter.
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