Static Files and folders - the hidden bits
Dynamic Files - what the User Sees
The "information" popup windows are also built by a PHP script. The product number is passed to the script in the URL called as a parameter. The script reads that parameter (product number), then finds the static version of the "information" file matching the product number. The static version is displayed line by line, until the script finds the comment marker around the cross-reference table. It then reads the cross-reference table carefully, and when a partnumber is found, the PHP checks the directories to see if there are further information or image files (same method as shop listings). If further information or images are found, the icons are added, with URLs. At the end of the table, there is another comment marker, and the script then just displays the remainder of the static file.
Order to Print page:
The "order" area is written with PHP. The shop data text file is opened and read line by line. When a product code from the data file matches one submitted from the form (with quantity other than null), a line of "order" is written. The quantity is used to multiply the issue price, and the running total is increased. When the end of the shop data file is reached, the grand total (before post) is displayed.
The popup for editing the name and address is controlled by the CSS, for its position and visibility. Also, the CSS has specific entries for print media, so the printed version comes out in a sensible font size on a reasonable amount of paper.
If anyone wants the source code to all of this, please ask.