Technology 101 - IM The Web Guy

As a standard for all our web development projects we use Active Server Pages (ASP), DHTML, HTML and JavaScript.

Below is a short introduction to each of these Techologies.

ASP - Active Server Pages

What is an ASP File?

• An ASP file is just the same as an HTML file
• An ASP file can contain text, HTML, XML, and scripts
• Scripts in an ASP file are executed on the server
• An ASP file has the file extension ".asp"

How Does ASP Differ from HTML?

• When a browser requests an HTML file, the server returns the file
• When a browser requests an ASP file, IIS passes the request to the ASP engine.
• The ASP engine reads the ASP file, line by line, and executes the scripts in the file.
• Finally, the ASP file is returned to the browser as plain HTML

What can ASP do for you?

• Dynamically edit, change or add any content of a Web page
• Respond to user queries or data submitted from HTML forms
• Access any data or databases and return the results to a browser
• Customize a Web page to make it more useful for individual users
• The advantages of using ASP instead of CGI and Perl, are those of simplicity and speed
• Provides security since your ASP code can not be viewed from the browser
• Since ASP files are returned as plain HTML, they can be viewed in any browser
• Clever ASP programming can minimize the network traffic
  

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DHTML Technologies

DHTML stands for Dynamic HTML.

With DHTML a Web developer can control how to display and position HTML elements in a browser window.

HTML 4.0

With HTML 4.0 all formatting can be moved out of the HTML document and into a separate style sheet. Because HTML 4.0 separates the presentation of the document from its structure, we have total control of presentation layout without messing up the document content.

Cascading Style Sheets (CSS)

With CSS we have a style and layout model for HTML documents.

CSS was a breakthrough in Web design because it allowed developers to control the style and layout of multiple Web pages all at once. As a Web developer you can define a style for each HTML element and apply it to as many Web pages as you want. To make a global change, simply change the style, and all elements in the Web are updated automatically.

The Document Object Model (DOM)

DOM stands for the Document Object Model.

The HTML DOM is the Document Object Model for HTML. The HTML DOM defines a standard set of objects for HTML, and a standard way to access and manipulate HTML objects.

"The W3C Document Object Model (DOM) is a platform and language neutral interface that allows programs and scripts to dynamically access and update the content, structure, and style of a document".

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JavaScript

Allows you to write code to control all HTML elements.

What is JavaScript?

• JavaScript was designed to add interactivity to HTML pages
• JavaScript is a scripting language (a scripting language is a lightweight programming language)
• A JavaScript consists of lines of executable computer code
• A JavaScript is usually embedded directly into HTML pages
• JavaScript is an interpreted language (means that scripts execute without preliminary compilation)
• Everyone can use JavaScript without purchasing a license
  

What can a JavaScript Do?

• JavaScript gives HTML designers a programming tool - HTML authors are normally not programmers, but JavaScript is a scripting language with a very simple syntax! Almost anyone can put small "snippets" of code into their HTML pages
• JavaScript can put dynamic text into an HTML page - A JavaScript statement like this: document.write(" " + name + " ") can write a variable text into an HTML page
• JavaScript can react to events - A JavaScript can be set to execute when something happens, like when a page has finished loading or when a user clicks on an HTML element
• JavaScript can read and write HTML elements - A JavaScript can read and change the content of an HTML element
• JavaScript can be used to validate data - A JavaScript can be used to validate form data before it is submitted to a server, this will save the server from extra processing
• JavaScript can be used to detect the visitor's browser - A JavaScript can be used to detect the visitor's browser, and - depending on the browser - load another page specifically designed for that browser
• JavaScript can be used to create cookies - A JavaScript can be used to store and retrieve information on the visitor's computer

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