UA_NS4 = (document.layers) ? true : false;
UA_IE4 = (document.all && !(typeof print == 'object')) ? true : false;
UA_IE5 = (document.all && (typeof print == 'object')) ? true : false;
UA_lowTek = (!UA_IE5 && !UA_IE4 && !UA_NS4) ? true : false;
US_Mac = (navigator.appVersion.indexOf("Mac") != -1) ? true : false;
US_Win = (navigator.appVersion.indexOf("Win") != -1) ? true : false;
US_Win95 = (US_Win && (navigator.appVersion.indexOf("95") != -1)) ? true : false;
US_Win98 = (US_Win && (navigator.appVersion.indexOf("98") != -1)) ? true : false;
US_else = (!US_Win && !US_Mac) ? true : false;