TypeError: event is undefined

[Buppy]

Hi,

I have the following JS:

var event = window.event;
if (event.keyCode == 38) {  
    //do something      
}

However, I keep getting the following error - TypeError: event is undefined
This happens only on Firefox, for all other browsers this works fine.

Thanks

[dcdruck]

I don't think window.event is part of the standard. This might be helpful though: http://stackoverflow.com/questions/9813445/why-ff-says-that-window-event-is-undefined-call-function-with-added-event-list