Periodically invoking modules
The answer is yes. The import_html module has a few tools available for this. You can:


Build a custom module that makes use of hook_cron() to trigger importing import functions in import_html. This would be good for standard periodic import based on certain times of the day.
Utilize the module's Drush integration and use the drush import-html command inside a shell script that's executed with crontab. This would be good for periodic import as well as one time imports that you can do with the command line.


The module also has an API to take action upon various parts of its import process too if you need it (e.g. alerting site admins of new imported site content). 

As a starting point, you should review the documentation on the project page. It has a help document that walks you through the usage of the module. If #1 is your preferred goal, you'll want to get familiar with the Drupal API, so you can understand how to create modules and understand the code of import_html module. For #2, you'll need to install Drush, learn how to use the drush import-html, and write out a shell script.