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JavaScript Bible, Gold Edition part 23

JavaScript Bible, Gold Edition part 23. This book will bring programmers and non-technical professionals, including casual programmers and scripters, painlessly up to speed on all aspects of mastering JavaScript. Key topics include programming fundamentals, JavaScript language elements and how to use them effectively, and how to easily and efficiently add powerful new functionality to HTML documents and Java applets. | 68 Part III Document Objects Reference Because every event handler operates as both property and method I don t list these properties and methods as part of each object s definition in the next chapters. You can be assured this feature works for every JavaScript object that has an event handler starting with Navigator 3 and Internet Explorer 4. Object Model Smorgasbord A survey of the entire evolution of scriptable browsers from NN2 and IE3 through IE5.5 and NN6 reveals six yes six distinct document object model families. Even if your job entails developing content for just one current browser version you may be surprised that family members from more than one document object model inhabit your authoring space. Studying the evolution of the object model is extremely valuable for newcomers to scripting. It is too easy to learn the latest object model gadgets in your current browser only to discover that your heroic scripting efforts are lost on earlier browsers accessing your pages. Therefore take a look at the six major object model types and how they came into being. Table 14-1 lists the object model families in chronological order of their release and the browser versions that support them. Later in this chapter are some guidelines you can follow to help you choose the object model s that best suit your users appetites. Table 14-1 Object Model Families Model Browser Support Basic Object Model NN2 NN3 IE3 J1 IE3 J2 NN4 IE4 IE5 NN6 IE5.5 Basic Plus Images NN3 IE3.01 Mac only NN4 IE4 IE5 NN6 IE5.5 NN4 Extensions NN4 IE4 Extensions IE4 IE5 IE5.5 some features in all versions require Win32 OS IE5 Extension IE5 IE5.5 some features in all versions require Win32 OS W3C DOM I and II IE5 partial IE5.5 partial NN6 most Basic Object Model The first scriptable browser Netscape Navigator 2 implemented a very basic document object model. Figure 14-1 provides a visual guide to the objects that were exposed to scripting. The hierarchical structure starts with the window and .