Dynamic HTML: The Definitive Reference

Cross-Platform Strategies

If your DHTML application must run on both Netscape and Microsoft browsers, you have a choice of several deployment strategies to pursue: page branching, internal branching, common denominator design, and custom API development. In all likelihood, your application will employ a combination of these techniques to get the same (or nearly the same) results on both platforms. No matter how you go about it, you must know the capabilities of each browser to provide equivalent experiences for users of both browsers. The rest of this book is designed to help you understand the capabilities of each browser, so the material in this section is mostly about the different strategies you can use.

Page Branching

Web pages that use absolute-positioned elements degrade poorly when displayed in older browsers. The positioned elements do not appear where their attributes call for, and, even worse, the elements render themselves from top to bottom in the browser window, in the order in which they appear in the HTML file. Also, any elements that are to be hidden when the page loads appear in the older browsers in their source code order. To prevent users of older browsers from seeing visual gibberish, you should have a plan in place to direct users of non-DHTML-capable browsers to pages containing less flashy content or instructions on how to view your fancy pages. A server-side CGI program can perform this redirection by checking the USER_AGENT environment variable ...