1) The document discusses how to make web applications accessible to users with JavaScript disabled or who are using older browsers or mobile devices.
2) It recommends coding the basic page structure for the "lowest common denominator" and then using DOM scripting and JavaScript libraries to enhance the experience for newer browsers and devices.
3) The document provides tips on understanding your audience, adding accessibility features like links to turn off advanced options, and using techniques like yellow highlighting to help low-sighted users follow changes to the page.