NOTE: As you are viewing this page, you are seeing DHTML in action.

HTML, an initialism of HyperText Markup Language, is the is the language of the web. Actually it is not a programming language but a markup language which tells the browser on your computer how to display the page on the screen. . It provides a means to describe the structure of text-based information in a document—by denoting certain text as links, headings, paragraphs, lists, and so on—and to supplement that text with interactive forms, embedded images, and other objects. HTML is written in the form of tags, surrounded by angle brackets. However it is static in its representation of the data.

Dynamic HTML, or DHTML, is a collection of technologies used together to create interactive and animated web sites by using a combination HTML and some sort of programming language such as, a client-side scripting language like Javascript, a presentation definition framework (such as CSS), and the Document Object Model. Using a programming language to alter the markup allows for adaptation to the user and the environment. As the internet continues to evolve, this concept becomes more and more predominant and has led to the term Web 2.0.

DHTML allows scripting languages to change variables in a web page's definition language, which in turn affects the look and function of otherwise "static" HTML page content, after the page has been fully loaded and during the viewing process. Thus the dynamic characteristic of DHTML is the way it functions while a page is viewed, not in its ability to generate a unique page with each page load.

By contrast, a dynamic web page is a broader concept — any web page generated differently for each user, load occurrence, or specific variable values. This includes pages created by client-side scripting, and ones created by server-side scripting (such as PHP or Perl) where the web server generates content before sending it to the client.