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

    // 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_ns  = ((agt.indexOf('mozilla')!=-1) && (agt.indexOf('spoofer')==-1)
                && (agt.indexOf('compatible') == -1) && (agt.indexOf('opera')==-1)
                && (agt.indexOf('webtv')==-1));
    var is_ns2 = (is_ns && (is_major == 2));
    var is_ns3 = (is_ns && (is_major == 3));
    var is_ns4 = (is_ns && (is_major == 4));
    var is_ns4up = (is_ns && (is_major >= 4));
    var is_nsonly      = (is_ns && ((agt.indexOf(";nav") != -1) ||
                          (agt.indexOf("; nav") != -1)) );
    var is_ns5 = (is_ns && (is_major == 5));
    var is_ns5up = (is_ns && (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_ns2 || is_ie3) is_js = 1.0
    else if (is_ns3 || is_opera) is_js = 1.1
    else if ((is_ns4 && (is_minor <= 4.05)) || is_ie4) is_js = 1.2
    else if ((is_ns4 && (is_minor > 4.05)) || is_ie5) is_js = 1.3
    else if (is_ns5) 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_ns && (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;