var agt=navigator.userAgent.toLowerCase();
var appVer = navigator.appVersion.toLowerCase();
var is_minor = parseFloat(appVer);
var is_major = parseInt(is_minor);
var iePos = appVer.indexOf('msie');
if (iePos !=-1) {
is_minor = parseFloat(appVer.substring(iePos+5,appVer.indexOf(';',iePos)))
is_major = parseInt(is_minor);
}
var is_getElementById = (document.getElementById) ? "true" : "false"; 
var is_getElementsByTagName = (document.getElementsByTagName) ? "true" : "false";
var is_documentElement = (document.documentElement) ? "true" : "false"; 
var is_ie = ((iePos!=-1));
var is_ie3 = (is_ie && (is_major < 4));
var is_ie4 = (is_ie && is_major == 4);
var is_ie4up = (is_ie && is_minor >= 4);
var is_ie5 = (is_ie && is_major == 5);
var is_ie5up = (is_ie && is_minor >= 5);
var is_ie5_5 = (is_ie && (agt.indexOf("msie 5.5") !=-1)); 
var is_ie5_5up =(is_ie && is_minor >= 5.5); 
var is_ie6 = (is_ie && is_major == 6);
var is_ie6up = (is_ie && is_minor >= 6);