Summary

This chapter has featured quite a few diversions and digressions, but these have been necessary to demonstrate the position and importance of the Document Object Model in JavaScript.

This chapter covered the following points:

• We started by outlining four of the main standards, HTML, ECMAScript, XML, and XHTML, and examined the relationships between them. We saw that a common aim emerging from these standards required stricter guidelines for coding HTML web pages. However, those guidelines in turn benefited the Document Object Model, making it possible to access and manipulate any item on the web page using script if web pages were coded according to these guidelines.

• We examined the Document Object Model and saw that it offered a browser- and language-independent method of accessing the items on a web page and resolved the problems that dogged version 4 of the browsers. We saw how the DOM represents the HTML document as a tree structure and how it is possible to navigate through the tree to different elements and use the properties and methods it exposes to access the different parts of the web page.

• While sticking to the standards provides the best method for manipulating the contents of the web page, none of the main browsers yet implements it in its entirety. We looked at the two most up-to-date examples, IE 6 and NN 7, and saw how they provided a strong basis for creating dynamic, inter-operable web pages due to their support of the DOM.