isNN = document.layers ? 1 : 0; 
function noContext(){return false;}
function noContextKey(e) {
    if(isNN){
        if (e.keyCode == 96){ return (false);}
    } else {
        if (event.keyCode == 96){ return (false);}
    }
}
function noClick(e){
    if(isNN){
        if(e.which > 1) {return false;}
    } else { 
        if(event.button > 1){return false;}
    }
}
if(isNN){ 
    document.captureEvents(Event.MOUSEDOWN);
}
document.oncontextmenu = noContext;
document.onkeypress    = noContextKey;
document.onmousedown   = noClick;
document.onmouseup     = noClick;
document.onmouseover	 = noContext;