PopUp Calendar with availability option.

Klik in field for demo

You can insert data in the data.js file, those dates will become coloured and not selectable.
I use is for a rental system, in this way the already rented days will not be selected again. And that means a lot less mailing for a available date.

Edited by Jaap van Boxtel

Based on the PopUp Calendar v2.1 script by PCI