Actually, I don't believe there is any way you can encrypt data coming from a form with any scripting language without using a Secure Web Server. A secure web server is just like any other web server, but it uses a key to encrypt all incoming and outgoing data. Your browser recognizes this data and uses the key supplied by the web server and establishes a secure connection (when you see the little padlock in the lower right or left corner of your browser). From that point on all data transmissions are encrypted using the key. Without a secure server, all web traffic can be monitored -- CC numbers, personal information, passwords, etc. I don't think there are any web technologies out there currently that can create this sort of protection other than a secure server -- at least no technologies that don't require some sort of client-side download for you to run.