I am struggling with the implantation of a multiple file upload, where all files are selected and uploaded one after another instead of selecting all files by once. A nice feature would be to list what files are added. I followed the answer from Tanaike at this post here: Uploading multiple files in one folder with one form submission

Is this even possible in Google Apps Script?

Tanaike's solution is great, but is overwriting the existing selection in the input field

For example: User wants to upload 3 files. What the user is supposted to do, is to select file #1, open it, select file #2, open it, select file #3, open it and then upload all 3 files together.