Hooking action to button submiting cart

[kizbo]

Hello.

 

I wish to extend my cart form, as: when user click button submiting his cart, providing him a site with delivery, payment etc. I wish to send additonal data, i guess hook into this action, but the tricky thing is, i have additional inputs in cart where my client set custom delivery dates for his products:

 

Cart

-----------------

Product#1

Calendar#1 -> (data going to hidden input here)

Product#2

Calendar#2-> (data going to another hidden input here)

 

Something like that, i just want to send this data from hidden inputs to my very special table in mysql, i know how to pass this data using Database object and how to hook, i just need to know how i can pass this data when user clicks button, perhaps as POST? Im open to ideas (i need to pass order ID to database with this data to show products in order page on back-end)