what is DHTML?

Dynamic HTML or DHTML is a method of creating interactive web sites by using a combination of static markup language (such as HTML), a client-side scripting language (such as JavaScript), the presentation definition language (e.g. Cascading Style Sheets [CSS] ), and the Document Object Model. Like LAMP or Ajax, DHTML is not a technology in itself, but a term that refers to the use of a group of technologies together.

Though the term "dynamic web page" can refer to any specific web page that is generated differently for each user, load occurrence, or per specific variable values, those pages with this type of "dynamic" content should not be confused for DHTML.
Web pages with this type of dynamic content, though still dynamic web pages, are a result of either server-side scripting (such as PHP or Perl), which generates unique content prior to sending the page to the visitor; or as a result of client-side scripting that is run immediately upon page load, before the static page content is visually generated.

DHTML, as described above, is a term specifically reserved for those pages which utilize client-side scripting (such as JavaScript) to effect changes in variables of the presentation definition language (such as CSS), which in turn will effect the look and function of otherwise "static" HTML page content, after the page has been fully loaded and during the viewing process. In effect, the dynamic characteristic of DHTML is found in how it acts and functions as each page is being viewed, not in its ability to generate a unique page with each specific page load.

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relevant books about DHTML

• Dynamic HTML: The Definitive Reference

• W3
• the Advantages of Using Valid HTML
• more information about web design
• web development blog category
• Wikipedia definition