prevent default function pivotal listeners yui

i have web page where i'd remap ctrl+n opposite behavior. i followed yui's instance register pivotal listeners duty called nonetheless firefox still creates new browser window. things seem work glorious ie7. i stop new window arrangement up?

example:

var kl2 = new yahoo.util.keylistener(document, { ctrl:true, keys:78 },
             {fn:function(event) {
                     yahoo.util.event.stopevent(event); // doesn't help
                     alert('click');}});
kl2.enable();

it illusory mislay default behavior. google docs overrides ctrl+s save your request instead bringing adult firefox's save dialog. i attempted instance above ctrl+s nonetheless firefox's save dialog still pops up. given google stop save dialog opening adult i'm certain there's proceed hinder many default keyboard shortcuts.