Kiosk Link Blocker v1.4
Kiosk Link Blocker is designed for Kiosk mode users, using a kiosk format. This add-on will allow you to specify which pages to allow only (disabling all others) or which pages to deny only (allowing all others), there is also an exceptions option if you want to allow a domain but not all of its pages or the flip of that deny a domain except some of its pages.
This can either be configured via the settings screen or alternatively via an external JSON file that will get loaded in each time the browser is opened and stored in the Firefox local storage to save spamming the external JSON web server.
After initial config, restart Firefox and all should be working.
Please be aware, this will not block popups and new windows it will only block the browser from navigating to unwanted pages in the same browsing tab. If you wish to know how to make Firefox not allow opening of new tabs and windows and instead load them on the current open tab, please don't hesitate to email me.