Javascript & Jquery defining a global variable?

Javascript & Jquery defining a global variable?

I am trying to define a global jquery object variable so that I can access
it from different functions.
This is what I am doing:
var object_list = $("#object__list");
var list_length = object_list.find("li").length;
$(document).on('keydown', '#object_list', function(event) {
//both of these don't work
alert(object_list);
alert(list_length);
});
Well,, for some reason this is not working (the first alert gives me NULL
and the second gives me 0, which is not).
Why aren't my global variables working..??
Thanks!!