Touchscreen and PHP Application...

Do touchscreens use a special coding format, or do they just mirror mouse behavior? For instance, if I were to make a PHP application for a simple POS retail system, would a touchscreen enabled monitor be compatible? If I had 3 big buttons (HTML form), and someone clicked on them, I'd assume they would react in the same way as if you were clicking on them with a mouse, correct?

 

PHP runs server-side, it has nothing to do with the client's hardware. How the touchscreen acts is up to the hardware and the OS.