[jQuery] Problem with keyup event from Learning jQuery 1.3

[EricC]

Hi I am currently learning jQuery from the book Learning jQuery 1.3
and I have run across a block of code that is not working for me in FF
or Safari. Here it is copied straight from the book (page 64)

$(document).ready(function() {
$(document).keyup(function(event) {
switch (String.fromCharCode(event.keyCode)) {
case 'D':
$('#switcher-default').click();
break;
case 'N':
$('#switcher-narrow').click();
break;
case 'L':
$('#switcher-large').click();
break;
}
});
});


I tested the next step that accomplishes the same thing with different
code but I would like to understand why this is not working. Any help
would be appreciated.

Cheers,

Eric