Problems detecting CTRL + KEY in Firefox on Ubuntu

[TxusLopez]

Hi,

I'm trying to detect the combo CTRL + P using javascript, but it's impossible.
I can detect the CTRL key, but no the 'P' key. So I cannot do:

if(ev.ctrlKey && ev.keyCode=80){
alert("yes!");
}

INFO:
Ubuntu 11.10 (oneiric)
GNOME 2.32.1
Firefox for Ubuntu canonical 1.0


Thanks