The Arduino web server hosts a web page that displays four analog input values and the state of three switches. The web page allows four LEDs to be controlled – two LEDs are controlled using checkboxes and two LEDs are controlled using buttons.
When more than one computer (web browser) is connected to the Arduino web server, then outputs (LEDs) switched on using one computer will be updated on the other computer – i.e. when a checkbox is clicked to switch an LED on from one computer, the checkbox will also be checked on the other computer automatically.
The following video shows two computers connected to the Arduino web server and as changes are made on the web page on one computer, they are updated on the other.