Getting js to php post

I have an order script which I found that seems to fit the bill for what is required. I need to put the information into a php processing script.

The part that I am unclear on is in the top section, there are product, qty, unit price ext price and the totals I am unsure how to get into the php.

I had played with giving them an id then setting it into a php variable, but not having much luck.

Anyone point me in the right direction?

Here is a link

Thank you