function Is ()
{   // convert all characters to lowercase to simplify testing
    var agt=navigator.userAgent.toLowerCase();

    // *** BROWSER VERSION ***
    // Note: On IE5, these return 4, so use is.ie5up to detect IE5.
    this.major = parseInt(navigator.appVersion);
    this.minor = parseFloat(navigator.appVersion);

    this.nav  = ((agt.indexOf('mozilla')!=-1) && (agt.indexOf('spoofer')==-1)
                && (agt.indexOf('compatible') == -1) && (agt.indexOf('opera')==-1)
                && (agt.indexOf('webtv')==-1));
    this.nav2 = (this.nav && (this.major == 2));
    this.nav3 = (this.nav && (this.major == 3));
    this.nav4 = (this.nav && (this.major == 4));
    this.nav4up = (this.nav && (this.major >= 4));
    this.navonly      = (this.nav && ((agt.indexOf(";nav") != -1) ||
                          (agt.indexOf("; nav") != -1)) );
    this.nav5 = (this.nav && (this.major == 5));
    this.nav5up = (this.nav && (this.major >= 5));

    this.ie   = (agt.indexOf("msie") != -1);
    this.ie3  = (this.ie && (this.major < 4));
    this.ie4  = (this.ie && (this.major == 4) && (agt.indexOf("msie 5.0")==-1) );
    this.ie4up  = (this.ie  && (this.major >= 4));
    this.ie5  = (this.ie && (this.major == 4) && (agt.indexOf("msie 5.0")!=-1) );
    this.ie5up  = (this.ie  && !this.ie3 && !this.ie4);

    // KNOWN BUG: On AOL4, returns false if IE3 is embedded browser
    // or if this is the first browser window opened.  Thus the
    // properties is.aol, is.aol3, and is.aol4 aren't 100% reliable.
    this.aol   = (agt.indexOf("aol") != -1);
    this.aol3  = (this.aol && this.ie3);
    this.aol4  = (this.aol && this.ie4);

    this.opera = (agt.indexOf("opera") != -1);
    this.webtv = (agt.indexOf("webtv") != -1);

    // *** JAVASCRIPT VERSION CHECK ***
    // Useful to workaround Nav3 bug in which Nav3
    // loads <SCRIPT LANGUAGE="JavaScript1.2">.
    if (this.nav2 || this.ie3) this.js = 1.0
    else if (this.nav3 || this.opera) this.js = 1.1
    else if ((this.nav4 && (this.minor <= 4.05)) || this.ie4) this.js = 1.2
    else if ((this.nav4 && (this.minor > 4.05)) || this.ie5) this.js = 1.3
    else if (this.nav5) this.js = 1.4
    // NOTE: In the future, update this code when newer versions of JS
    // are released. For now, we try to provide some upward compatibility
    // so that future versions of Nav and IE will show they are at
    // *least* JS 1.x capable. Always check for JS version compatibility
    // with > or >=.
    else if (this.nav && (this.major > 5)) this.js = 1.4
    else if (this.ie && (this.major > 5)) this.js = 1.3
    // HACK: no idea for other browsers; always check for JS version with > or >=
    else this.js = 0.0;

    // *** PLATFORM ***
    this.win   = ( (agt.indexOf("win")!=-1) || (agt.indexOf("16bit")!=-1) );
    // NOTE: On Opera 3.0, the userAgent string includes "Windows 95/NT4" on all
    //        Win32, so you can't distinguish between Win95 and WinNT.
    this.win95 = ((agt.indexOf("win95")!=-1) || (agt.indexOf("windows 95")!=-1));

    // is this a 16 bit compiled version?
    this.win16 = ((agt.indexOf("win16")!=-1) ||
                  (agt.indexOf("16bit")!=-1) || (agt.indexOf("windows 3.1")!=-1) ||
                  (agt.indexOf("windows 16-bit")!=-1) );

    this.win31 = ((agt.indexOf("windows 3.1")!=-1) || (agt.indexOf("win16")!=-1) ||
                  (agt.indexOf("windows 16-bit")!=-1));

    // NOTE: Reliable detection of Win98 may not be possible. It appears that:
    //       - On Nav 4.x and before you'll get plain "Windows" in userAgent.
    //       - On Mercury client, the 32-bit version will return "Win98", but
    //         the 16-bit version running on Win98 will still return "Win95".
    this.win98 = ((agt.indexOf("win98")!=-1) || (agt.indexOf("windows 98")!=-1));
    this.winnt = ((agt.indexOf("winnt")!=-1) || (agt.indexOf("windows nt")!=-1));
    this.win32 = ( this.win95 || this.winnt || this.win98 ||
                   ((this.major >= 4) && (navigator.platform == "Win32")) ||
                   (agt.indexOf("win32")!=-1) || (agt.indexOf("32bit")!=-1) );

    this.mac    = (agt.indexOf("mac")!=-1);
    this.mac68k = (this.mac && ((agt.indexOf("68k")!=-1) ||
                               (agt.indexOf("68000")!=-1)));
    this.macppc = (this.mac && ((agt.indexOf("ppc")!=-1) ||
                               (agt.indexOf("powerpc")!=-1)));
}

var is;
var isIE3Mac = false;
// this section is designed specifically for IE3 for the Mac

if ((navigator.appVersion.indexOf("Mac")!=-1) && (navigator.userAgent.indexOf("MSIE")!=-1) && (parseInt(navigator.appVersion)==3))
       isIE3Mac = true;
else   is = new Is();  
    

compatible = true;

if(is.mac && is.ie) {
   compatible = false; 
}

if(!compatible && (window.location.href+"").indexOf("continue=1")==-1) {
    window.location="/error/not_supported_browser.html";    
}