Added a new one, complete re-write for the heck of it. New version abuses arrays and has no input capabilities.
Very simple Brainf*ck Interpreter in JavaScript
The input method is terrible, needs to be changed for it to be useful.
Sample Code (I did not write this, found at www.99-bottles-of-beer.net) 99 Bottles of Beer on the Wall:
>>>>>++++++++[<+++++++++>-]<+[>>[>]+[<]<-]>++++++++++[<+++++
+++++>-]<[>>[+>]<[<]<-]<++++++++[>++++++++[>>->->->>>>>>>>>>
>->>>->>>>>>->->->->>->>>->>>>->>>>>->->>>>>>->>>>->>>>>->->
>>>>->>>->>>>>>>->-[<]<-]>>++>++>->>+>++>++>+>>>>++>>->+>>->
>>>++>>+>+>+>--->>->+>+>->++>>>->++>>+>+>+>--->>-->>+>>->+>+
>>->>+>++>+>+>->+>>++>++>->>++>->>++>+>++>+>>+>---[<]<<-]>>>
++++>++++>+++>--->++>->->->>[-]>->-->[-]>+++>++>+>+++>--->>>
--->[-]>+>+>+>--->[-]>+++>++>+>+++>->+++>>+++>++>---->->->+>
--->[-]>->---->-->>+++>++>+>>+++>->++>++>+>->+++>+++>---->--
>-->+++>++++>->+++>---->--->++>>+>->->---[[<]<]+++++++++[<+<
+++++++++++>>-]<<[>>>>>[<]>[.>]>--[>.>]<[<<]>++>>>[.>]>[>]>[
.>]<[[<]<]>>[.>]>--[>.>]<[<<]>++>>>[.>]>[.>]>[>]>[.>]<[[<]<]
<<[<]>>>+<[>-]>[>]<[+++++++++[<+<->>>>>+<<<-]+<<[>>-]>>>[<]<
<<++++++++++>>[>>[-]+<<-]>>-<<]>>>-[>]>-<<[<]>[.>]>--[>.>]<[
<<]>++>>>[.>]>[>]>[.>]<.[[<]<]<<[<]>>-<-]