Create custom event handler occurs when receive messages from keyboard -

When we receive messages from the keyboard or press a button, how do I create my own event handler and then We write output in a text box ...

This javascript has some sample code.

  function AlertOnKeyPress (e) {var code; If (! E) var e = window.event; If (e.keycode) code = e.keyCode; And if (E. Joe) code = E. that; Var character = string. Framer code (code); Warning ('character was' + character); }