Answer 1

1))
Use Ajax. And paste your code url into XMLHttpRequest.

2))
We will get a response data

Its my code. This code containe: how to access whole codes from a Sololearn profile
https://code.sololearn.com/Wxi8XFo2Q58H/?ref=app

Then

Use ZipJS library for compressing your codes.

ZipJS documentation:
https://gildas-lormeau.github.io/zip.js/

You can generate a zip file of any file type.
Then make a download link for that zip file

How to create a file downloader using JavaScript:
https://stackoverflow.com/questions/1066452/easiest-way-to-open-a-download-window-without-navigating-away-from-the-page