>If I get some spare time soon I think I'll build the Ajax-only >validation thing as a proof of concept. I'm willing to bet that the >performance difference between it and pure client-side validation >will be imperceptible in most cases. If it's noticable and obvious >that the user experience would be better with hybrid client-side/Ajax >validation then I'll throw my support firmly behind that option.
Please not AJAX-only - we do still want to validate on POST, too, as the user might just have JavaScript disabled or is using IE with settings that don't allow the XmlHttpRequest object ... But AJAX validation callbacks done as asynchronous requests that just trigger some "colour this red" logic won't really be a big burdon on performance - since they happen asynchronously. But you need to keep them fast and short enough to make sure that you don't run out of threads - most browsers set some upper limit of how many requests can run in parallel, and XHR shared that numbe of threads ... bye, Georg
