This JavaScript code detects Netscape IP address for Netscape users only.

<script language="JavaScript" type="text/javascript">
netscapeTest = parseInt(navigator.appVersion)
explorerTest = navigator.appName.indexOf("Microsoft") + 1
function netscapeThree() {
if (navigator.javaEnabled()) {
userDomain = java.net.InetAddress.getLocalHostName()
return (userDomain.toString())
} else {
return null
}
}
function netscapeFour() {
if (navigator.javaEnabled()) {
baseAddress = java.net.InetAddress.getLocalHost()
userDomain = baseAddress.getHostName()
return (userDomain.toString())
} else {
return null
}
}
if ((explorerTest == "0") && (netscapeTest == "3")) {
domainName = netscapeThree()
}
else if ((explorerTest == "0") && (netscapeTest == "4")) {
domainName = netscapeFour()
}
else {
domainName = "using Internet Explorer?  Then I don\'t know what your IP address is."
}
alert('Are you really ' + domainName + ' ?')
</script>

Simply Cut and Paste Script code
Be sure to properly place script position in head of html
Works for Netscape only. IE users will receive an alert message
This script has been in the DesignerWiz.com Public Library.