Well, i am starting scripting at JS and i asking for help:

<body bgcolor="000000" text="ffffff">

<script language="javascript">
<!-- ...
document.write("This browser is version " + navigator.appVersion)
document.write(" of <B> " + navigator.appName +"</B>.")
// ... -->

Sincerily i don't know what is wrong with the script, the only thing i know is that isn't working, instead of giving a message with the browser version it is giving a message written "undefined"
that is all