Welcome to Part IV. Up until now, most of the scripts you've written will work in the latest versions of either of today's most popular browsers: Netscape Navigator and Internet Explorer. Between these two, your scripts will work for a vast majority of the Web audience.
As you move on, however, you'll start working with topics that aren't so compatible. The latest features, such as dynamic HTML, tend to work differently on different browsers, and some features are specific to one or another.
The new DOM (Document Object Model) standard has eliminated many of the most troubling browser differences, but you'll still run into situations where you need to create different code for different browsers. You can use JavaScript to differentiate between browsers, supporting all of them either within one page or on separate pages.
Hour 14 covers the following topics:
Using JavaScript to get browser information
Making a page browser-specific
Dealing with browsers without JavaScript support
Creating a script for multiple browser support