This is just a test for Spectrum Lab's built in HTTP server. To see it in action, do not load it as a file with your browser ! Instead, enable the server inside SpecLab, then enter the IP address of the machine on which SL is running.
Example (here using the IP address where SL is running, this one only works via LAN, not WWW):
http://192.168.0.22/ 

If you have no local network, but want to test the server locally, use IP address 127.0.0.1 which always 'loops back' to the local machine.
Both server ('host') and client (your web browser) can run on the same PC then.
If the above link doesn't work even though SpecLab is running, the most likely reason is that SL's built-in web server is disabled (which it is, by default, for security) or because windows or the windows firewall has blocked it.

At the time of this writing, the HTTP server in SpecLab allows you to...


Further reading: