I'm working on a page/project that would allow our customers to check a webpage to see if their network is ready to plug in a cloud based device. The page should query a specific HTTPS URL, check it returns anything other than HTTP 200, then go to the next URL. At the end of the test, it should give a summary of what isn't reachable.  Ideally, it should be purely HTML based but I'm struggling to find ways to do this. I also need it to check the certificate status of a URL to make sure the network isn't using behind a firewall running SSL inspection. Is this possible just by using HTML?
I can easily do this in python/requests and could just send them a script to run on their computer, but the goal of this project is to make this as seamless as possible. We just send them a link and a non IT person could check if the network is ready then report to us what test failed.
You can't do these things with pure html. you need to use javascript and also you should know that you cant do network layer operations with just application layer technologies. so simple answer is no you can't do it just by using html.
HTML based network testing tool