Could we see some demos of basic usage for solving linear algebra homework, i.e., can I haz a CAS in the JavaScript console of my browser? Also I'd like to see

Could we see some demos of basic usage for solving linear algebra homework, i.e., can I haz a CAS in the JavaScript console of my browser? Also I'd like to see some 2D plotting examples of basic functions of the form f:R->R. I'm looking for a simple .js lib for plotting...