I release today jquery.terminal, a jQuery plugin to embed a terminal in web pages. It has several base commands and can be customized in order to add application-specific commands. It has a powerful operator mechanism to group command together (allowing to pipe commands and more combinations). And it is very, very geek.
Try the demo online!
I really love the command flow, that the outputs of one command serve as additional arguments for another one. With real computer terminals, there are two input methods: arguments in the command line, or the standard input. I made here life much more easier: a single input way. Actually, it has been designed as a data stream with filters which can map values to other ones.
Follow the development on GitHub.