var BrowserOK = BrowserMSIE3 = ie3 = ns3 = ns6 = false
var ie4 = (document.all)? true:false
var ns4 = (document.layers)? true:false

if (!(ns4 || ie4)) {
	if ((navigator.appName == "Netscape") && navigator.appVersion.substring(0,1) > 4) {
		ns6 = true
		ie4 = true
		}
	else if ((navigator.appName == "Netscape") && navigator.appVersion.substring(0,1) == 3) ns3 = true;
	else if ( navigator.appVersion.indexOf("MSIE") != -1 )  ie3 = true;
	}

if (ns3 || ns4 || ie4) {
	BrowserOK = true;
	}
else BrowserOK = false;