function getMajorVersion() {
    var nVer = navigator.appVersion;
    var nAgt = navigator.userAgent;
    var browserName = navigator.appName;
    var fullVersion = '' + parseFloat(navigator.appVersion);
    var majorVersion = parseInt(navigator.appVersion, 10);
    var nameOffset, verOffset, ix;

    // In MSIE, the true version is after "MSIE" in userAgent
    if ((verOffset = nAgt.indexOf("MSIE")) != -1) {
        browserName = "Microsoft Internet Explorer";
        fullVersion = nAgt.substring(verOffset + 5);
    }
    // In Opera, the true version is after "Opera" 
    else if ((verOffset = nAgt.indexOf("Opera")) != -1) {
        browserName = "Opera";
        fullVersion = nAgt.substring(verOffset + 6);
    }
    // In Chrome, the true version is after "Chrome" 
    else if ((verOffset = nAgt.indexOf("Chrome")) != -1) {
        browserName = "Chrome";
        fullVersion = nAgt.substring(verOffset + 7);
    }
    // In Safari, the true version is after "Safari" 
    else if ((verOffset = nAgt.indexOf("Safari")) != -1) {
        browserName = "Safari";
        fullVersion = nAgt.substring(verOffset + 7);
    }
    // In Firefox, the true version is after "Firefox" 
    else if ((verOffset = nAgt.indexOf("Firefox")) != -1) {
        browserName = "Firefox";
        fullVersion = nAgt.substring(verOffset + 8);
    }
    // In most other browsers, "name/version" is at the end of userAgent 
    else if ((nameOffset = nAgt.lastIndexOf(' ') + 1) < (verOffset = nAgt.lastIndexOf('/'))) {
        browserName = nAgt.substring(nameOffset, verOffset);
        fullVersion = nAgt.substring(verOffset + 1);
        if (browserName.toLowerCase() == browserName.toUpperCase()) {
            browserName = navigator.appName;
        }
    }
    // trim the fullVersion string at semicolon/space if present
    if ((ix = fullVersion.indexOf(";")) != -1) fullVersion = fullVersion.substring(0, ix);
    if ((ix = fullVersion.indexOf(" ")) != -1) fullVersion = fullVersion.substring(0, ix);

    majorVersion = parseInt('' + fullVersion, 10);
    if (isNaN(majorVersion)) {
        fullVersion = '' + parseFloat(navigator.appVersion);
        majorVersion = parseInt(navigator.appVersion, 10);
    }
    return majorVersion;
}