I have a huge product editor, with over 80 fields. I'm on my 8th generation of it now. The last update I made was to create a huge Javascript object of the entire thing, and small saves just update the object in the DOM, Full saves use $ajax to update the database. Validation is on the fly using blur When clicking through the tabs, the data is loaded from the object. It took me a 2 week to write, over 10K lines of Javascript, but so far so good, no complaints after 3 months of running it. It's a combination of Javascript and JQuery, but mostly Javascript.