Chapter 52. Application: Outline-Style Table of Contents
IN THIS CHAPTER
Multiple frames
Clickable images
Persistent data
Dynamic HTML positioning
Reading XML data via AJAX
In your web surfing, you may have encountered sites that implement an expandable, outline type of table of contents. I've long thought that these elements were great ideas, especially for sites with lots of information. An outline, such as the Windows Explorer or text-style Macintosh Finder windows, enables the author to present a large table of contents in a way that doesn't necessarily take up a ton of page space or bandwidth. From listings of top-level entries, a user can drill down to reveal only those items of interest.
No matter how much I like the idea, however, I dislike visiting these sites. A server program responds to each click, chews on my selection, and then sends back a completely new screen, showing my choice expanded or collapsed. After working with outlines in the operating system and outliner programs on personal computers, the delays in this processing seem interminable. It occurred to me that implementing the outline interface as a client-side JavaScript can significantly reduce the delay problem and make outlines a more viable interface to a site's table of contents. This chapter documents the process that went into a JavaScript-powered outliner, which works with all modern browsers.
The Implementation Plan
I admit to approaching the outline technique the first time without a specific data-display ...
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