What We'll Be Working On
The component we'll be working on in this book controls a special mode in your browser that prevents users from leaving the current domain or a set of safe domains. Once enabled, this weblock mode is password protected and persists until it is turned off by the password holder. It can be used to make the browser into a safe viewer for children, or for targeted "kiosk browsing," where the content is restricted to a particular server. Web Lock User Interface shows the icon that is used to activate the web lock mode (leftmost in the status bar) once you have installed the WebLock component and the extra user interface.
Most of the actual work in the WebLock component is preparing the component itself, finding the XPCOM interfaces the component needs to use, and hooking into existing functionality within the Gecko Browser.