DHTML for Not Yet Techies

DHTML is an advance on the standard stuff for computer careers, which is HTML. It’s the tags that tell browsers how to display the text and graphics on a web site. So what’s D-HTML? It is an advance on HyperText Markup Language and important for any Internet computer career.

Here I’m quoting from the FAQ:

"Dynamic HTML (DHTML) is the name given by both Netscape and Microsoft to the use of the Document Object Model, Cascading Style Sheets, and client-side scripting to make Web pages more interactive. By using these technologies, developers can make their Web pages change on-the-fly and interact with users without having to reload."

This allows for a lot of cool animation, plus some useful interaction.

Some interaction has been possible with Java, Active-X, JavaScript and VBScript. DHTML expands the range and power of this. Before Dynamic HTML, to add or view such dramatic changes in a website, you needed a special plug-in to your browser, such as Macromedia’s Flash.

For example, this page could be made to actually change when you – the web site visitor – took some action, such as clicking on the text. Then all the text could be switched to the Helvetica bold italic font, with every other paragraph turned purple.

Now, I can’t think of any good reason for doing that, and I don’t think you want to visit web sites where the appearance changes for no good reason. Many sites are no doubt better for students playing and making sites that have weird and "cool" special effects than for anyone doing serious business or research on the web. Nevertheless, it does have its possibilities. Perhaps someday, the web sites that expect me to read deep purple text displayed against a black starry backdrop will allow me to change to change their design.

This whole idea or device of having individual page elements (such as type font and color) and their hierarchy open to change is called the Document Object Model (DOM). The Document Object Model defines the properties and methods for the various elements on an HTML page. Essentially, every page element is treated as an "object" which properties that can be operated upon and changed.

Cascading style sheets are related to this. They are essentially a better and easy way to design pages by coding the HTML within web sites. Therefore, they are part of the DOM which can now be changed while someone is actually viewing the site.

Microsoft’s DOM allows for changes of all aspects of an HTML page. Netscape’s implementation is more limited but is supposed to be expanded with future releases, so it won't miss DHTML.

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