Usability Testing of Inline Form Validation: 40% Don’t Have It, 20% Get It Wrong - Articles - Baymard Institute
I saw Christian speak on this topic at Smashing Conference in Barcelona. Here, he takes a long hard look at some of the little things that sites get wrong when doing validating forms on the fly. It’s all good sensible stuff, although it sounds a bit medical when he takes about “Premature Inline Validation.”