var isNav4 = null;
var isNav4up = null;
var isNav3 = null;
var isNav3up = null;
var isIE4 = null;
var isIE4up = null;
var isIE3 = null;
var isIE3up = null;
var isNav = null;
var isIE = null;
var is4up = null;

// alert(navigator.appVersion.charAt(0));

if (navigator.appVersion.charAt(0) >= "4") {
    is4up = true;
}

if (navigator.appName == "Netscape") {
    isNav = true;
    if (navigator.appVersion.charAt(0) == "4") {
		// alert('isNav4');
        isNav4 = true;
    }
    if (navigator.appVersion.charAt(0) >= "4") {
		// alert('isNav4up');
        isNav4up = true;
    }
    if (navigator.appVersion.charAt(0) >= "3") {
		// alert('isNav3up');
        isNav3up = true;
    }
    if (navigator.appVersion.charAt(0) == "3") {
		// alert('isNav3');
        isNav3 = true;
    }
}
else if (navigator.appVersion.indexOf("MSIE") != -1) {
    isIE = true;
    if (navigator.appVersion.charAt(0) == "4") {
        isIE4 = true;
    }
    if (navigator.appVersion.charAt(0) >= "4") {
        isIE4up = true;
    }
    if (navigator.appVersion.charAt(0) >= "3") {
		// alert('isIE3up');
        isIE3up = true;
    }
    if (navigator.appVersion.charAt(0) == "3") {
		// alert('isIE3');
        isIE3 = true;
    }
}