Integrating Captivate content with a website

It looks like you're coming at this with a web development mindset, which is good! If you just jump in the deed end, you'll spend a lot of time creating administration, file management, security and reporting functions that are available by installing and configuring a Learning Management System (LMS) or Content Management System (CMS).

Once you ask if you can manage captivate files for many students and many courses you're looking at multiple inter-related tables in a database structure. Not really a small project, even for the 1st course and 1st user. (That's your minimum viable product, MVP)

Take a look at CMSMatrix.org and see what kind of options you'd like, I'd suggest you start with Moodle or Drupal. This is a great place to start, as features are listed and discussed; licensing is detailed, as are prices. There are some that are opensource, and many have a small-business/non-profit/educational license, that may be reduced capacity, but will have a reduced licensing fee. Also, some of them offer a free developer license to get you started.

Even if you DO build it yourself, it's worth looking at the features and security requirements for a few comparable tools to see what your baseline of effort should be.

Will you charge for this as a service, then you'll need a decent security profile to ensure your customers see your tools as secure.

Will you collect fees ON the site, then you need higher level security or an API connection to a funds management site like PayPal or Bitcoin.

You could always send the variables to local storage and the html page could read it from there using JavaScript. You could also populate variables in the html page.

It's also possible using local storage to keep scores for different users.