function populateOS() {
        // Ultimate client-side JavaScript client sniff.
        // (C) Netscape Communications 1999.  Permission granted to reuse and distribute.
        // Revised 20 April 98 to add is_nav5up and is_ie5up (see below).

        // Everything you always wanted to know about your JavaScript client
        // but were afraid to ask. Creates "is_" variables indicating:
        // (1) browser vendor:
        //     is_nav, is_ie, is_opera
        // (2) browser version number:
        //     is_major (integer indicating major version number: 2, 3, 4 ...)
        //     is_minor (float   indicating full  version number: 2.02, 3.01, 4.04 ...)
        // (3) browser vendor AND major version number
        //     is_nav2, is_nav3, is_nav4, is_nav4up, is_nav5, is_nav5up, is_ie3, is_ie4, is_ie4up
        // (4) JavaScript version number:
        //     is_js (float indicating full JavaScript version number: 1, 1.1, 1.2 ...)
        // (5) OS platform and version:
        //     is_win, is_win16, is_win32, is_win31, is_win95, is_winnt, is_win98
        //     is_os2
        //     is_mac, is_mac68k, is_macppc
        //     is_unix
        //        is_sun, is_sun4, is_sun5, is_suni86
        //        is_irix, is_irix5, is_irix6
        //        is_hpux, is_hpux9, is_hpux10
        //        is_aix, is_aix1, is_aix2, is_aix3, is_aix4
        //        is_linux, is_sco, is_unixware, is_mpras, is_reliant
        //        is_dec, is_sinix, is_freebsd, is_bsd
        //     is_vms
        //
        // See http://www.it97.de/JavaScript/JS_tutorial/bstat/navobj.html and
        // http://www.it97.de/JavaScript/JS_tutorial/bstat/Browseraol.html
        // for detailed lists of userAgent strings.

        //
        // Note: you don't want your Nav4 or IE4 code to "turn off" or
        // stop working when Nav5 and IE5 (or later) are released, so
        // in conditional code forks, use is_nav4up ("Nav4 or greater")
        // and is_ie4up ("IE4 or greater") instead of is_nav4 or is_ie4
        // to check version in code which you want to work on future
        // versions.

        // 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.
        var is_major= parseInt(navigator.appVersion);
        var is_minor= parseFloat(navigator.appVersion);

        var is_nav= ((agt.indexOf('mozilla')!=-1) &&(agt.indexOf('spoofer')==-1)
                    &&(agt.indexOf('compatible')== -1) &&(agt.indexOf('opera')==-1)
                    &&(agt.indexOf('webtv')==-1));
        var is_nav2= (is_nav &&(is_major== 2));
        var is_nav3= (is_nav &&(is_major== 3));
        var is_nav4= (is_nav &&(is_major== 4));
        var is_nav4up= (is_nav &&(is_major >= 4));
        var is_navonly= (is_nav &&((agt.indexOf(";nav") != -1) || (agt.indexOf("; nav") != -1)));
        var is_nav5= (is_nav &&(is_major== 5));
        var is_nav5up= (is_nav &&(is_major >= 5));

        var is_ie= (agt.indexOf("msie") != -1);
        var is_ie3= (is_ie &&(is_major < 4));
        var is_ie4= (is_ie &&(is_major== 4) &&(agt.indexOf("msie 5.0")==-1));
        var is_ie4up= (is_ie  &&(is_major >= 4));
        var is_ie5= (is_ie &&(is_major== 4) &&(agt.indexOf("msie 5.0")!=-1));
        var is_ie5up= (is_ie  && !is_ie3 && !is_ie4);

        var is_aol= (agt.indexOf("aol") != -1);
        var is_aol3= (is_aol && is_ie3);
        var is_aol4= (is_aol && is_ie4);

        var is_opera= (agt.indexOf("opera") != -1);
        var is_webtv= (agt.indexOf("webtv") != -1);

        // *** JAVASCRIPT VERSION CHECK ***
        // Useful to workaround Nav3 bug in which Nav3
        // loads <SCRIPT LANGUAGE="JavaScript1.2">.
        var is_js;
        if(is_nav2 || is_ie3) is_js= 1.0
        else 
        if(is_nav3 || is_opera) is_js= 1.1
        else 
        if((is_nav4 &&(is_minor <= 4.05)) || is_ie4) is_js= 1.2
        else 
        if((is_nav4 &&(is_minor > 4.05)) || is_ie5) is_js= 1.3
        else 
        if(is_nav5) is_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(is_nav &&(is_major > 5)) is_js= 1.4
        else 
        if(is_ie &&(is_major > 5)) is_js= 1.3
        // HACK: no idea for other browsers; always check for JS version with > or >=
        else 
        is_js= 0.0;

        // *** PLATFORM ***
        var is_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.
        var is_win95= ((agt.indexOf("win95")!=-1) ||(agt.indexOf("windows 95")!=-1));

        // is this a 16 bit compiled version?
        var is_win16= ((agt.indexOf("win16")!=-1) || (agt.indexOf("16bit")!=-1) ||(agt.indexOf("windows 3.1")!=-1) || (agt.indexOf("windows 16-bit")!=-1));  

        var is_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".
        var is_win98= ((agt.indexOf("win98")!=-1) ||(agt.indexOf("windows 98")!=-1));
        var is_winnt= ((agt.indexOf("winnt")!=-1) ||(agt.indexOf("windows nt")!=-1));
        var is_win2k = ((agt.indexOf("windows nt 5.0")!=-1));
        var is_winxp = ((agt.indexOf("windows nt 5.1")!=-1)); 
        var is_win32= (is_win95 || is_winnt || is_win98 || ((is_major >= 4) &&(navigator.platform== "Win32")) || (agt.indexOf("win32")!=-1) ||(agt.indexOf("32bit")!=-1));

        var is_os2= ((agt.indexOf("os/2")!=-1) || (navigator.appVersion.indexOf("OS/2")!=-1) || (agt.indexOf("ibm-webexplorer")!=-1));

        var is_mac= (agt.indexOf("mac")!=-1);
        var is_mac68k= (is_mac &&((agt.indexOf("68k")!=-1) || (agt.indexOf("68000")!=-1)));
        var is_macppc= (is_mac &&((agt.indexOf("ppc")!=-1) || (agt.indexOf("powerpc")!=-1)));

        var is_sun= (agt.indexOf("sunos")!=-1);
        var is_sun4= (agt.indexOf("sunos 4")!=-1);
        var is_sun5= (agt.indexOf("sunos 5")!=-1);
        var is_suni86= (is_sun &&(agt.indexOf("i86")!=-1));
        var is_irix= (agt.indexOf("irix") !=-1);    // SGI
        var is_irix5= (agt.indexOf("irix 5") !=-1);
        var is_irix6= ((agt.indexOf("irix 6") !=-1) ||(agt.indexOf("irix6") !=-1));
        var is_hpux= (agt.indexOf("hp-ux")!=-1);
        var is_hpux9= (is_hpux &&(agt.indexOf("09.")!=-1));
        var is_hpux10= (is_hpux &&(agt.indexOf("10.")!=-1));
        var is_aix= (agt.indexOf("aix") !=-1);      // IBM
        var is_aix1= (agt.indexOf("aix 1") !=-1);    
        var is_aix2= (agt.indexOf("aix 2") !=-1);    
        var is_aix3= (agt.indexOf("aix 3") !=-1);    
        var is_aix4= (agt.indexOf("aix 4") !=-1);    
        var is_linux= (agt.indexOf("inux")!=-1);
        var is_sco= (agt.indexOf("sco")!=-1) ||(agt.indexOf("unix_sv")!=-1);
        var is_unixware= (agt.indexOf("unix_system_v")!=-1); 
        var is_mpras= (agt.indexOf("ncr")!=-1); 
        var is_reliant= (agt.indexOf("reliantunix")!=-1);
        var is_dec= ((agt.indexOf("dec")!=-1) ||(agt.indexOf("osf1")!=-1) || (agt.indexOf("dec_alpha")!=-1) ||(agt.indexOf("alphaserver")!=-1) || (agt.indexOf("ultrix")!=-1) ||(agt.indexOf("alphastation")!=-1)); 
        var is_sinix= (agt.indexOf("sinix")!=-1);
        var is_freebsd= (agt.indexOf("freebsd")!=-1);
        var is_bsd= (agt.indexOf("bsd")!=-1);
        var is_unix= ((agt.indexOf("x11")!=-1) || is_sun || is_irix || is_hpux || 
                     is_sco ||is_unixware || is_mpras || is_reliant || 
                     is_dec || is_sinix || is_aix || is_linux || is_bsd || is_freebsd);

        var is_vms= ((agt.indexOf("vax")!=-1) ||(agt.indexOf("openvms")!=-1));
        if(is_winnt)
           document.login.OS.value = "WinNT" 
        if(is_win2k)
           document.login.OS.value = "Win2000" 
        if(is_winxp)
           document.login.OS.value = "WinXP" 
        if(is_win95)
           document.login.OS.value = "Win95" 
        if(is_win98)
           document.login.OS.value = "Win98" 
           
  }