Ask : Why does the bind/shorthand method of keyboard event , always occured warning ?

Ask : Why does the bind/shorthand method of keyboard event , always occured warning ?

Hai all masters and members here , im new bie here . may i ask something ?
Why does the keyboard event : keyup , keypress , keydown on bind/shorthand method of it , always occured warning ?
im using jQuery 1.4.2 and the warning on my firefox error console is like this :

" The 'charCode' property of a keyup event should not be used. This value is meaningless "

and here is my code :
-----------------------------------------------------------------------
jQuery(document).ready(
    function(){
        //start


       
        jQuery(document).bind(
            "keyup",
            function(e){
                if(e.keyCode==122 || e.keyCode==27){
                    alert("testing esc/f11 fullscreen detection");
                }
            }
        );
       


        //finish
    }
);
-----------------------------------------------------------------------
Is this a problem ? Or nothing ? How can we fix this ?
Anyone would help me? please? thanks , regards

Jendal Bakar