101 UX Principles

Chapter #45. Validate Data Entry as Soon as Possible

Validation on a form means showing the user visual feedback that there's a problem with some of the information they've painstakingly entered. Validate data entered into a field as soon as possible, when the user moves to the next field, so you know they're done typing in the current one.

Client-side validation isn't always technically possible, but you should aim for it wherever you can because the "round trip" to the server and back is frustrating if there are errors.

Tell the user to try again before they submit the form

There are lots of techniques for doing this, including plenty of third-party ...