My beginning HTML class has two chapters that delve into the basics of scripting. It also touches on Dynamic HTML (DHTML). Now, there is no way that the class can give a thorough understanding of Javascript and DHTML in addition to HTML and CSS and do an adequate job. Each topic or technology would require its own course to fully grasp the subjects. So understanding the BIG IDEA has to be the goal. The BIG IDEA is to understand how javascript intersects with the DOM and CSS to control the display of HTML elements. If you walk away with that BIG IDEA, then as a designer, you are a better position how to work with code that is already out there. Most people that enter into web design are visual people. You first want to develop a sense of which technology has which role in a web page so you understand what to research further.
I would recommend that everyone look into jQuery if you want to understand more about where DHTML is today. DHTML is an old term. It is not used very much anymore. The same languages and approaches are now under a new name – AJAX. According to Wikipedia, “Like DHTML and LAMP, Ajax is not a technology in itself, but a group of technologies. Ajax uses a combination of HTML andCSS to mark up and style information. The DOM is accessed with JavaScript to dynamically display, and to allow the user to interact with, the information presented. JavaScript and the XMLHttpRequest object provide a method for exchanging data asynchronously between browser and server to avoid full page reloads.” Programmers are building libraries of functions in Ajax and use a special Application Programming Interface (API) so designers can easily call them from HTML. The result is called iQuery.