Excellent Arduino Ethernet Shield Web Server Tutorial

I love the tutorials on the starting electronics website!

There is one thing I am trying to do, but does not work the way I want it to work.

According to the AJAX tutorials on the startingelectronics website it's possible to create a html button
and turn on a device (Relay, led, buzzer whatever).
This absolutely works.

But what about increasing or decreasing a value of a variable by 1 (only when button is pushed once)?

If you make a button with a link in it, the url will be something like http://192.168.1.177/?Button.
And as long as this url is working and the page is refreshing or kept alive, the links is working.
This is very good when you are turning on a led, relay or something like that.

But when you want to increase a value of a variable by 1 at the push of a button, the value of the variable keeps on going up as the page refreshes or is being "kept alive".

Does anyone know how to do this properly or a good tutorial for this?

Thanks in advance!