IN THIS CHAPTER
Determining which browser the user has
Branching scripts according to the user's operating system
Detecting plug-in support
To that end, browsers provide objects that expose as much about the client computer and browser as is feasible within accepted principles of preserving a user's privacy. In addition to providing some of the same information that server-side programs receive as environment variables, these browser-level objects may also include information about how well equipped the browser is with regard to plug-ins and Java. Another object reveals information about the user's video monitor, which may influence the way your scripts calculate information displayed on the page.
The objects in this chapter don't show up on the document object hierarchy diagrams, except as free-standing groups. The IE4+ object model, however, incorporates these environmental objects as properties of the
window object. Because the