MACROMEDIA 38028779 - Macromedia Dreamweaver - Mac, Using Manual, Page: 394 / 582

Chapter 16 394
About XML
XML is the Extensible Markup Language, a markup language for structured
documents. You can think of it as being like a generalization of HTML that lets
you define your own tags. XML is derived from SGML, the Standard Generalized
Markup Language; like SGML, XML is a language for defining sets of tags and
the relationships among them.
Tags in XML look similar to HTML tags: they consist of a tag name plus optional
attributes, surrounded by angle brackets. As with HTML, an opening tag and a
closing tag (in which the tag name is preceded by a slash) are used to mark the
content between the tags. One syntactical difference is that in XML, an empty
tag (one that uses only a single tag, such as
<img>
, instead of an opening tag and a
closing tag containing text or other material) must end with a slash just before the
closing angle bracket. For example, an
<img>
tag in XML might look like this:
<img src="test.png" />
True XML is much stricter and less forgiving about its syntax than HTML is; files
that do not strictly conform to XML syntax are rejected by XML parsers.
XML provides a way to mark literal strings, which can include tags that should
not be parsed: an element called a
CDATA
section, which includes a literal string in
square brackets. Anything inside the square brackets is not parsed by the XML
parser. Dreamweaver exported XML makes extensive use of
CDATA
sections.
A full introduction to XML is beyond the scope of this book. For more information
about XML, see “HTML and Web technologies resources” on page 25.