How do I back out of web site when web page covers normal icons?

The terminology for systems which integrate and manage computer-based learning has changed over the years. Terms which are useful in searching for earlier materials include: "Integrated Learning Systems" (ILS), "Computer Assisted Instruction" (CAI), "Computer Based Training" (CBT),"Computer Managed Instruction" (CMI), "Interactive Multimedia Instruction" (IMI), "Technology Enhanced Learning" (TEL), "Technology Based Learning" (TBL), and "Web Based Training" (WBT).