DHTML debabbled
When I started the Debabblog, one of my worries was that I might run out of things to write about too quickly. Here it is a few months later, and I'm stilling getting through what I consider the "basics". Over the last few weeks, I've covered a group of core internet topics including Javascript, CSS, and the DOM. Together, this motley band forms, well, kind of a mess. We affectionately call that mess DHTML.What is DHTML?
The "D" in DHTML stands for Dynamic. The HTML is the same HTML that we know and love, the markup language used to create virtually every web page on the internet. The problem with our friend HTML is that it has always been limited by essentially being a server-side creation. In other words, web pages are created on a server and then sent to the "client" (being you, the web surfer) in their final and more or less unchanging state. If you want more information or just a slightly different layout, you have to go back to the server and request yet another web page.
Client-side scripting languages, like Javascript, were essentially designed to allow a web page to have a little life left in it once it reaches the reader. As Javascript evolved, CSS separated content from presentation, and the DOM allowed elements of a web page to be directly controlled, the options for changing a web page on the fly in new and exciting ways became almost limitless. DHTML is essentially the realization of those options, crafting web pages that are highly interactive and respond to users in real-time.
What's in it for me?
In theory, DHTML sounds great, and in small doses, it can be invigorating stuff. Unfortunately, almost by definition, it defies the original simplicity of HTML. HTML was designed to be read consistently across many different computers and operating systems, allowing the internet to be standardized in a way that was never before possible. The complexity of DHTML, and different implementations of the various scripting behaviors and object models, have left us with dynamic pages that are very difficult to build and often behave differently (and sometimes quite badly) for different users.
That's not to say that DHTML is of no value, just that the dream of building completely interactive websites has met with many, many obstacles. The basic building blocks of DHTML can add key interactivity and better usability to websites, as long as you use them sparingly and test them thoroughly. Currently, other client-side technologies, including AJAX, are testing the waters of interactivity, and many changes are likely to come on that front. So, use DHTML thoughtfully and carefully, and stay tuned.
