What is DHTML?
Dynamic HTML, or DHTML, is an umbrella term for a collection of technologies used together to create interactive web sites by using a combination of a static markup language (such as XHTML), a client-side scripting language (such as PHP, JavaScript), a presentation definition language (such as CSS), and the Document Object Model.
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" XHTML 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) where the web server generates content before sending it to the client.