Written by Mike Faust
Note the "language" parameter of the <script> tag, which describes the specific scripting language to be used to interpret the script.
A Script by Any Other Name
The DOM is a hierarchical structure used to access all of the objects within an HTML document. The World Wide Web Consortium (W3C) has a defined DOM standard. The current version, referred to as Level 3, was defined in 2004. Each browser's level of compliance with the W3C standard varies. The general "tree" structure shown in Figure 1 is common to all implementations, however.
Figure 1: An illustration of DOM's tree structure.
The variety of browsers and versions of browsers makes it difficult to come up with a comprehensive list of differences in compatibility. Rather than try to explain all of these differences, let's focus on how to identify and deal with the differences when they occur.