[eluser]xwero[/eluser]
In the other post you say you don't want to change the javascript but you are using php files to check the input remotely. these urls need to change to something like index.php/ajax/validation/email.
The tab keypress isn't the most userfriendly way to instantiate the validation as it will move the cursor a field down and if a users click on another field the validation will not happen until the user presses the submit button.
inparo gave you a good preset helping you out with the serverside code but i don't see how you want to integrate your previous code without changing your javascript code.
