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If you ever wondered what kinds of risks pioneers take, look no further than many of the DHTML features of Netscape Navigator 4. Designed well before the first CSS and DOM standards crystallized, Navigator 4 became a victim of a sea-change in approaches to style sheets and document object models. Its efforts to bring JavaScript syntax to style sheet rules, to add the <layer> tag to the HTML vocabulary, and to place the bulk of a page's dynamism into a separate layer object all failed to gain acceptance in the W3C working groups. At the last minute, some of the nascent CSS language made it into Navigator 4, but it was fairly fragile when applied to complex pages involving tables and forms.
For the brief time period during which Navigator 4 was the only DHTML game in town, the lack of standards support was not a problem. But when Microsoft released Internet Explorer 4, with its radically different object model approach, developers had to jump through hoops to write DHTML code that accomplished the same tasks in both browsers. Even then, the power of dynamic page reflow in IE 4 made many DHTML effects essentially impossible to duplicate in the mostly static body content of Navigator 4 pages.
If Netscape's unsuccessful pioneering attempts weren't bold enough, the development of the next generation of the Netscape browser engine (handed to the separate Mozilla group) called for an even bolder move. Those nonstandard features from Navigator 4 would not carry over into the next generation. A lot of JavaScript code tailored to Navigator 4 runs in no other browser. In other words, Navigator 4 has become a dead-end development platform, whose installed base will only decrease over time.
Despite the fact that some organizations have continued to standardize on Navigator 4 while waiting to migrate to a more modern browser platform, this edition of Dynamic HTML: The Definitive Reference cuts the cord with the Navigator 4 past. If you need assistance and examples of scripting Navigator 4 DHTML, consult the first edition of this title.
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| 2. Cross-Platform Compromises |  | 2.3. Internet Explorer DHTML |
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