function Browser() {

    var ua, s, i;

    this.isIE = false;  // Internet Explorer
    this.isOP = false;  // Opera
    this.isNS = false;  // Netscape
    this.version = null;

    ua = navigator.userAgent;

    s = "Opera";
    if ((i = ua.indexOf(s)) >= 0) {
        this.isOP = true;
        this.version = parseFloat(ua.substr(i + s.length));
        return;
    }

    s = "Netscape6/";
    if ((i = ua.indexOf(s)) >= 0) {
        this.isNS = true;
        this.version = parseFloat(ua.substr(i + s.length));
        return;
    }

    // Treat any other "Gecko" browser as Netscape 6.1.

    s = "Gecko";
    if ((i = ua.indexOf(s)) >= 0) {
        this.isNS = true;
        this.version = 6.1;
        return;
    }

    s = "MSIE";
    if ((i = ua.indexOf(s))) {
        this.isIE = true;
        this.version = parseFloat(ua.substr(i + s.length));
        return;
    }
}

var browser = new Browser();