This script looks at the IP address that the laptop (wireless) gets. At work I always get a 128.x.x.x type of address so the browser gets redirected based on that.
I had to upgrade the java plugin to Version 1.4.2_03 (build 1.4.2_03-b02) to make sure the getAddress() always got the latest DHCP address.
<META http-equiv="expires" content="0">
ip = java.net.InetAddress.getLocalHost().getAddress();
/* Upgrade from byte to int and maskoff the sign bit */
subnet = ip & 0xff;
if (subnet == 128)