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Chapter 1
HTML
HTML is the primary format for web-based content. As you undoubtedly know,
the purpose of HTML is to "mark up" a text using tags, sometimes with attributes
to provide instructions on how the document is structured and how it should look
when displayed in a browser.
Tags and elements
An HTML tag looks like this: . Most tags in HTML are paired, with a
start and end tag. A tag may also have attributes, such as type="text/
javascript", and may also surround some content. When we talk
about the tag, plus the attributes and its content, we use the term element.
For example, to indicate that a piece of text is particularly important, we would put it
inside of the tags:
The important thing.
By default, most visual browsers render the content of the element as
bold text as seen here:
The important thing.
HTML's evolution has been a rough one. Initially, it was designed just to provide
structural information about the contents. But somewhere along the line, it also
became a tool for encoding layout and styling information. Combining the two
seemingly similar ideas of structure and style seemed like a good idea. But in
practice, it made for some very messy code.
The family of HTML specifications can be found online
at http://www.w3.org/html/.
On another front, XML (which we will look at in a moment) evolved separately.
Then, at some point, reconciliation between the HTML standards and the XML
standards was attempted. The outcome of this endeavor was XHTML (HTML in
XML). XHTML is now considered to be the right way to write HTML. In this book, we
will strive to use well-formed XHTML. You may notice this in the following ways:
•
•
All tags and attribute names will be in lowercase.
All tags will be closed. That means a tag will either appear in the opening
and closing pairs (), or as a single self-closing tag
(—note the forward slash (/) before the closing angle bracket (>)).
• All documents will start with an XML declaration ( ) and a
document type declaration ().
This material is copyright and is licensed for the sole use by Richard Ostheimer on 18th June 2009
2205 hilda ave., , missoula, , 59801