Adam 08 December 2009 Thanks for your response Bruce. I know what you are saying about the 80-20 rule but I guess in my world, there are a lot of forms that require more advanced features. – let’s say registration, returns process, checkout process, manage multiple addresses and payment details in the account areas etc. Also, on your point of the browser vendors coming up with styling of errors. That causes another issue. What if the project requirements for whatever reason (opinion, accessibility, usability) contradict what the browser vendor decides to implement? What if for example the browser puts a red border around the erroneous input in question but I want a red exclamaton icon as a bg to the associated label with a little more padding? We would seem to have two branches of visual errors – the way the browser deems it and the way the project requirements deem it? I like the idea of standardising these features but I see a lot of issues with it. And putting a pattern attribute on an input is mixing behaviour/business-logic/js layer with the content/mark-up/html layer – although this is a picky point, i think it is valid.