You do not necessarily need an active connection to the Internet to view this text. The text has built-in navigational tools that you can use without relying on your browsing program. Actually, none of this is absolutely necessary, but the text will work best if you follow these instructions. You can also use the navigational tools that your browser offers to go back and forth between previously viewed pages. Most of the time, however, the buttons built into the text will be sufficient for navigation.
Every page has a 'button bar' at the bottom.
If you can not see it, scroll down until they become visible. In addition, several types of buttons are built into the text, and the first word of examples, definitions, or theorems is a link to more information. If you are lost in the text, you can always click on the Map button. You will see an overview of the text, with your current location shown in red.