Progress bar for HTMLs (Flask backend)

I need code to integrate with my HTML files that show a progress bar, My backend is in Flask. The code must be configurable and you should demonstrate how I can integrate the code in my HTMLs. I am ware of HTML and Bootstrap progress bar, but what I need from you is to show me status of jobs (percentage complete) when page is loading. If you understand the requirement, you can chat with me. I have fixed budget around $15-$20 for this work. I will pay only when code is working on my end. You must how how to intgerate progress bar with jobs that are run on Flask server.