What is HTML?

HTML stands for Hypertext Markup Language and it is the original computer language used to build web pages. Hypertext is essentially a link – click on text and it takes you to other related information. A markup language is a way to describe how information should be formatted.

To better understand this, take a look at Microsoft Word with all of its icons, toolbars, menus and fancy features. Imagine none of those features were there. Better yet open up Notepad, the bare bones text editor on Windows. How would make your heading bold? How would you change the size of the text? Insert an image or graphic? If there were no menu or functions for that, how would someone reading your document know how you wanted it to be formatted? Enter a markup language. In HTML, a markup language specifically for the web, you would use special tags to format your document:

<b>My Title</b>

<i>My Italicized Subtitle</i>

<p>My paragraph. It's a short one.</p>

b = bold in early HTML, i=italics and p=paragraph. Some of these tags have been replaced with newer, more fashionable versions, but let’s keep it simple.

HTML is a language made up of tags (normally in pairs – front and back), which wrap around the text that you want to format and tell the web browser (Internet Explorer, Firefox, Netscape, etc) how to display the content. There are special tags for the various parts of the document that also inform web browsers how to read the document as a whole. That is the basics of web development. In order to display text, images, links, video or audio on a web page, the proper tag or tags must be invoked.

What is XML?

XML (eXtensible Markup Language) is generalized markup language that can be used to transfer and store data. Whereas all HTML tags are pre-defined – you can’t just use <paragraph> instead of <p> and expect web browsers to understand it – with XML, the designer of the system decides what the tags are. XML is often used to hold structured data and can be used as a simple database for some web applications. For example, here’s a grocery list:


<groceries>
<fruit>
<oranges>Navel</oranges>
<apples>Granny Smith</apples>
<bananas>Organic</bananas>
</fruit>
<cereal>Frosted Flakes</cereal>
</groceries>


Now, that I have my data, I could write a program to allow me to display that data, or update it, perhaps from a website or my cell phone. XML is used for a wide variety of purposes because of its flexibility.

HTML and XML are both children of SGML (Standard Generalized Markup Language) the granddaddy of markup languages. SGML was created in the 1960s to make information readable by computers.

What is XHTML?

XHTML (eXtensible Hypertext Markup Language) is essentially an upgraded version HTML which combines it with XML. It uses the much more strict syntax of XML in order to whip our lazy friend HTML into shape. Historically, web browsers have been very forgiving of mistakes in HTML. However, even the simplest syntax error in an XML document will produce a fatal error.

XHTML is recommended by many  in order to increase compatibility with a variety of devices. While web browsers are forgiving of code errors, other devices may not be. These days, more and more organizations want their website viewable not only on computers, but on mobile phones, PDAs, gaming systems and other devices that haven’t been invented yet. XHTML brings a more disciplined and streamlined approach to HTML, which is a strong base for the future of development.

Your comments are welcomed below.

You can reach Leslye at leslye@reflectiondigital.com

How about including weblinks on authored CDs?  Check out David Ryan’s post: http://tinyurl.com/64td2m