Netscape and Microsoft 4.0 browsers expose a lot of new host objects to JavaScript's control. The ability to manipulate fragments of a single HTML document, known as Dynamic HTML puts a number of new techniques at the script writer's (and HTML author's) disposal. Using these techniques, a browser window graduates from a mostly static information display device, to a (possibly highly) animated and interactive communication media. This evolution allows browsers to take up some of the space normally reserved by other tools, such as in the area of presentation graphics.
Regrettably, both vendors continue to add incompatible features as they anticipate or innovate ahead of the standardization process. Fortunately, the Document Object Model is both standard-driven and central to these new features. Because of its more recent release, Internet Explorer 4.0 has far greater support for this standard than Netscape's 4.0 browser offering does.