var NS4 = document.layers;
var NS6 = document.getElementById && !document.all;
var IE4 = document.all;
var	IE5 = (IE4 && navigator.appVersion.indexOf("5.")!=-1);
var isMac = (navigator.appVersion.indexOf("Mac") != -1);
var isMenu = (NS4 || (IE4 && !isMac) || (IE5 && isMac));
var  ver4 = (NS4 || IE4);

if (!ver4) event=null;