window.open udfra navigator.appName

Hvorfor virker dette script ikke i netscape 4.08?

<html>

<head><SCRIPT LANGUAGE="JavaScript">

<!--
if (navigator.appName == 'Netscape'){
    if (screen.height > 768) { location.href = 'netscape_storre_end_768.html'; }
    if (screen.height == 768) { uar = window.open("1024ie/index.htm","uar","toolbar=0,location=0,status=0,menubar=0,scrollbars=yes,resizable=0,width=778,height=585"); }
    if (screen.height == 600) { location.href = 'netscape600.html'; }
    if (screen.height == 480) { location.href = 'netscape480.html'; }
    if (screen.height < 480) { location.href = 'netscape_mindre_end_480.htm'; }
}           
    else {
    if (navigator.appName == 'Microsoft Internet Explorer'){
        if (screen.height > 768) { uar = window.open("1024ie/index.htm","uar","toolbar=0,location=0,status=0,menubar=0,scrollbars=yes,resizable=0,width=778,height=585"); }
        if (screen.height == 768) {uar = window.open("1024ie/index.htm","uar","toolbar=0,location=0,status=0,menubar=0,scrollbars=yes,resizable=0,width=778,height=585"); }
        if (screen.height == 600) { uar = window.open("800ie/index.htm","uar","toolbar=0,location=0,left=89,top=36,status=0,menubar=0,scrollbars=yes,resizable=0,width=622,height=468"); }
        if (screen.height == 480) { uar = window.open("640ie/index.htm","uar","toolbar=0,location=0,left=7,top=0,status=0,menubar=0,scrollbars=yes,resizable=0,width=622,height=419"); }
        if (screen.height < 480) { location.href = 'explorer_mindre_end_480.htm'; }
    }
    else if (navigator.appName == '*'){
        if (screen.height > 768) { location.href = 'andenbrowser_storre_end_768.html'; }
        if (screen.height == 768) { location.href = 'andenbrowser768.html'; }
        if (screen.height == 600) { location.href = 'andenbrowser600.html'; }
        if (screen.height == 480) { location.href = 'andenbrowser480.html'; }
        if (screen.height < 480) { location.href = 'andenbrowser_mindre_end_480.htm'; }
    }   
}   
//-->

</SCRIPT>
<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
<meta name="ProgId" content="FrontPage.Editor.Document">
<title>Vent</title>
</head>

<body bgcolor="#FFFFFF">
<p><font size="-1" face="Verdana, Arial, sans-serif">Der åbnes nu et vindue med vores hjemmeside. Kommer du til at lukke vinduet skal du blot trykke på "Opdater" i menulinjen.</font></p>

</body>

</html>