NN4 (and NN3 I think but I haven't checked the code with it) allows
that by calling into Java:
var localhost = java.net.InetAddress.getLocalHost();
var hostname = localhost.getHostName();
var hostIP = localhost.getHostAddress();
alert('You are visiting from host ' + hostname
+ ' with ip address ' + hostIP);
The only way with IE to use Java is an applet but the above code
(transcribed into Java) run in an applet is reported to return
localhost
for the hostname respectively
127.0.0.1
for the ip address.
So all you can do for IE (and Opera and NN6) is to use server side
assists meaning a cgi script or php script dynmically returning the
REMOTE_ADDR cgi variable. I have set up such an assists at
http://www.csdn.net/jshelper/ipAddress.php
which returns a statement of the form
var ipAddress = '123.123.123.123;
so that a script can then access the variable
ipAddress
to read the value e.g.