ASP beginner’s tutorial

PART TWO

Useful information

To understand how ASP works, you need to have some knowledge about the technologies that support it and work with it:

What is a web browser?

This is the programme you use to view (or hear) and otherwise interact with resources on the internet. Typical examples of browsers are Internet Explorer, Netscape, Opera, Firefox and Lynx. Whilst nominally based on the worldwide web "standard", competition and non-standard enhancements mean that most browsers interpret web in a different ways. For the sake of this tutorial the internet resources will be termed "web pages". Web browsers are referred to as the "client" and receive pages from web servers.

What is the difference between a server and a client?

When you surf the internet, you download pages to your web browser and view (or hear) them. The web pages are stored on a web server, which delivers them to your browser (or client). Anything that happens before a page reaches you is called "server-side" and anything that happens once the page is on your computer is called "client-side".

What are static web pages?

A static page is a "fixed" page that uses plain HTML page, and is made up of text, images, tables, links etc. The HTML that exists on the server is the same HTML that is displayed by the client (your browser). Whenever you visit the page (using the same browser/operating system), the page you see (or hear) will be the same and will not change no matter what you do to the page.

What is HTML?

Hyper Text Mark-up Language is a descriptive "language" that describes the content of a web page using "mark-up" tags. It is not a prescriptive, absolute language and relies on the interpretation of your web browser to determine how the page looks (or sounds). HTML is based on Standard Generalized Mark-up Language (SGML) framework You may have come across other SGML derived-languages such as XML, XHTML and WML.

What are HTML tags?

HTML tags are used to identify elements on a web page and describe what your browser should do with them. For example, if a web designer wants to emphasise a particular piece of text, the <strong> tag may be used:

<strong>this is important!</strong>

Which in your browser appears as:

this is important!

Most tags comprise an opening and a closing pair. Other, hopefully self-explanatory, tags include <table>, <title> and <input>. Tags can have various attirbutes that further describe how the element looks. For example, and <input> tag has many attributes, some of which describe its type, name and value, for example:

<input type="text" value="enter your name" size="35">

Which in your browser appears as an input text box thus:

Where can I learn more about HTML?

The following link goes to a very useful HTML tutorials. To make the most of this ASP tutorial, you will need a working knowledge of HTML.

W3C Schools HTML tutorial

What are dynamic web pages?

Some pages can change depending on certain conditions. Examples of dynamic pages are those that change depending on your choices or preferences, are created "on the fly", or adapt to the type of browser you are using. Dynamic pages may exist in some form on the server or they may not exist at all!

Dynamic pages are controlled using scripting languages. Some pages react locally on you computer using client-side script, perhaps producing a pop-up error message when you fill out a text field incorrectly. Other pages may react after you have submitted them using server-side script, for example, resulting in an error message on the returned page.

What are scripting languages?

Web scripting languages are, generally, used to produce simple routines to create or control various elements on a web page. Common script languages include VBScript, JavaScript and JScript. Script functions can be processed on the server or on your browser. Some browsers cannot, or are set not to process client-side scripts. For the purposes of this tutorial, the scripting language used is VBScript.

What is a database?

A database is a collection of, usually, related data organised in some logical way, for example user names, engine parts and product details. The data can be retrieved, changed, deleted and searched using ASP script.

Next: introduction to ASP

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