Alternative to captcha - using JQuery and ajax to 'time' form input

Opinions/thoughts?: http://docs.jquery.com/Tutorials:Safer_Contact_Forms_Without_CAPTCHAs Basically it pulls the server time in background using an ajax call, and implements an MD5 encrypted value in a hidden field, and then you can double check the timing of form input to sort of verify that it was real time, and not a form of automated process, by a spambot/robot as such. Only real issue here is it would require user to have cookies and javascript enabled, but anyway..? Stay well Jacob Kruger Blind Biker Skype: BlindZA '...fate had broken his body, but not his spirit...'