I understand that I can zip multiple file and download it as zip when the files are already exists on ther server. like this.

My question is, I have a dropdown list that prompt user download different section of a big form on the fly so I have header below for download it individually.

header("Content-type: text/plain");
header("Content-Disposition: attachment; filename=op_summary.lyx");

I need to add another function to download them all at ones. How can I implement it? Should I have download them in the server before zipping it and download to client?

I will also need a checkbox fundtion that pick multiple files according whichever files that user select.

Any suggestion will be helpful.