INTRODUCTION

TO

DHTML

TOPICS TO BE DISCUSSED……….

Introduction

Uses

Components

Difference between HTML and DHTML

Introduction

Dynamic Hyper Text Markup Language (DHTML) is a combination of

Web development technologies used to create dynamically changing

websites. Web pages may include animation, dynamic menus and text

effects. The technologies used include a combination of HTML, JavaScript

or VB script, CSS and the document object model (DOM).

Designed to enhance a Web user’s experience.

DHTML includes the following features:

Dynamic content, which allows the user to dynamically change Web page

Content.

Dynamic positioning of Web page elements

Dynamic style, which allows the user to change the Web page’s color, font,

size or content

Uses of DHTML

Animate text and images in their document, independently moving each

element from any starting point to any ending point, following a

predetermined path or one chosen by the user.

Embed a ticker that automatically refreshes its content with the latest news,

stock quotes, or other data.

Use a form to capture user input, and then process, verify and respond to

that data without having to send data back to the server.

Include rollover buttons or drop-down menus.

Components of DHTML

DHTML requires four independent components to work: HTML,

Cascading Style Sheets, Scripting and the Document Object Model.

Following is the description of each component.

HTML: HTML defines the structure of a Web page, using such basic

elements as headings, forms, tables, paragraphs and links.

Cascading Style Sheets (CSS): Similar to a template in a word-processing

document, a style sheet controls the formatting of HTML elements. Like in

traditional desktop publishing, one can use style sheet to specify page

margins, point sizes and leading. Cascading Style Sheets is a method to

determine precedence and to resolve conflicts when multiple styles are

used.

Scripting: Scripting provides the mechanisms to interpret user actions and

produce client-side changes to a page. For example, scripts can interpret

mouse actions (such as the mouse passing over a specified area of a page

through the event model) and respond to the action by using a set of

predefined instructions (such as highlighting the text activated by the

mouse action). Although DHTML can communicate with several scripting

languages, JavaScript is the de facto standard for creating cross-browser

DHTML pages.

Document Object Model (DOM): The DOM outlines Web page content in

a way that makes it possible for HTML elements, style sheets and scripting

languages to interact with each other. The W3C defines the DOM as "a

platform- and language-neutral interface that will allow programs and

scripts to dynamically access and update the content, structure, and style of

documents. The document can be further processed and the results of that

processing can be incorporated back into the presented stage."

Differences between HTML and DHTML:

HTML is a mark-up language, while DHTML is a collection of

technology.

DHTML creates dynamic web pages, whereas HTML creates static web

pages.

DHTML allows including small animations and dynamic menus in Web

pages.

DHML used events, methods, properties to insulate dynamism in HTML

Pages.

DHML is basically using JavaScript and style sheets in an HTML page.

HTML sites will be slow upon client-side technologies, while DHTML

sites will be fast enough upon client-side technologies.

HTML creates a plain page without any styles and Scripts called as

HTML. Whereas, DHTML creates a page with HTML, CSS, DOM and

Scripts called as DHTML.

HTML cannot have any server side code but DHTML may contain server

side code.

In HTML, there is no need for database connectivity, but DHTML may

require connecting to a database as it interacts with user.

HTML files are stored with .htm or .html extension, while DHTML files

are stored with .dhtm extension.

HTML does not require any processing from browser, while DHTML

requires processing from browser which changes its look and feel.

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