[Script] Abstract the keyCode on Firefox

To abstract the key value which users press on their keyboard, IE supports a method to approach this goal.

onkeypress="window.event.keyCode";

But FireFox does not support window.event. For cross-platform, We have to revise this method.

onkeypress="jsGetKeyCode(event)"
...
jsGetKeyCode(e){
var keyCode = window.event ? e.keyCode : e.which;
}