nicht angemeldet
etwa so?
<html>
<head>
<script language="javascript">
<!--
function go() {
window.location.href = "http://"+document.forms[0].elements[0].value+".domain.cx";
}
//-->
</script>
</head>
<body>
<form>
<input type="text"><input type="button" value="GO" onClick="go()">
</form>
</body>
</html>