var Zeile = '';
var CSSFile = '';

if ((navigator.appName == "Microsoft Internet Explorer")
        && (parseInt(navigator.appVersion.charAt(0)) >= 4)) {
    CSSFile = "pcssie.css";
    var BLang = navigator.browserLanguage;
}

if ((navigator.appName == "Netscape")
        && (parseInt(navigator.appVersion.charAt(0)) >= 4)) {
    CSSFile = "pcssne.css";
    var BLang = navigator.language;
}

if ((navigator.appVersion.indexOf("Macintosh") != -1)
        && (parseInt(navigator.appVersion.charAt(0)) >= 4)) {
    CSSFile = "pcssmt.css";
    var BLang = navigator.language;
}

Zeile = '<LINK REL="STYLESHEET"' + ' HREF="' + CSSFile + '"' + ' TYPE="TEXT/CSS"' + '>';
document.write(Zeile);