(Don't bother replying with "don't try to make your own encryption", this is an experiment for myself that I may use on experimental sites)

I am playing around with making my own encryption, based on OTP encryption. I just wanted you guys to take a look and tell me what you think.

Try it here:
http://otp.script-x.net/
(it has issues with spaces but I'm working on it)
Here is the source:
http://pastebin.com/DpsPWnpv