Question: I'm want to use client-side printing to print multiple documents but want some more control over the print functionality or print dialog. This is not possible in IE but I noticed that chrome browser has it own print dialog compared to the default windows print dialog.

Is there an API for the chrome print that I could use in JavaScript?

Answer: 
Your switch/case statements look like they could, and should, be replaced with table lookup -- for example, a 2D array where the first axis is indexed by `purchaseAmount > 100` (0 or 1) and the second axis is indexed by `deliveryDay` (0, 1, or 2).
I suggest you to store costs somewhere in database instead of not hard-coded. this will reduce your code to db connection and query.