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HTML
The Hypertext Markup Language (HTML) is the language
used to create web pages. Due to HTML editing software,
it's no longer a requirement to understand HTML to
create a web site. However, it is a good idea to learn
in case your favorite editor isn't available and you
have changes to make.
The HTML was created and is maintained by the World
Wide Web Consortium (W3C), a group located at MIT.
The last version that was released was HTML 4.0.
The way that the HTML works is to use "tags"
to tell a browser how to properly format a page. An
example of a tag and it's function is the bold tag,
<b>. Most tags come in a matching pair, an on
and an off. An off tag looks identical, except the
second character is a forward slash, /. Whatever information
you want formatted gets sandwiched between the on
an off tags. If you want to make some text bold, you
would do: <b>make this bold</b> and the
result on the screen would be:
make this bold
To see how a page was created using HTML, view the
source code in the browser's menu by clicking on View
and then Source or Page Source.
XHTML
The newest version of HTML is actually called XHTML
1.0. This version more closely follows the strict
rules of XML, which is discussed below. The purpose
for this change was to force correct coding and improved
consistency of the markup.
There aren't too many differences
between HTML and XHTML, but the differences are important:
- All tags and attribute names must be lower case
- All attribute values must be enclosed in quotes
- All tags must have a closing value. If a tag
does not have a matching closing tag, a forward
slash is the last character before the > in
the tag. For example:
<img src="my_picture.jpg" /> or
<br />
The future of web publishing will use XHTML, so
if you're starting out, learn this new standard.
XML
The Extensible Markup Language (XML) is a parent
language to HTML as XML also uses tags, but it is
more powerful than just describing format. XML has
strict rules about what types of data can appear
between the tags, and conversely the tags give additional
information about the data enclosed.
XML is also flexible as it allows you to create
new tags and define them in what is called a "Schema".
Just as the W3C defines the HTML tags, XML lets
you do the same for your own tags. However don't
expect a browser to understand any tag that you
create. The Schema for HTML is not open source.
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