XML.com FAQs > C. Authors of SGML (including writers of HTML: Web page owners)
Question:  C.13 Does XML let me make up my own tags?

No, it lets you make up names for your own elements. If you think tags and elements are the same thing you are already in trouble: read the rest of this question carefully.

Before we start this one, Bob DuCharme notes: Don't confuse the term `tag' with the term `element' . They are not interchangeable. An element usually contains two different kinds of tag: a start-tag and an end-tag, with text or more markup between them.

XML lets you decide which elements you want in your document and then indicate your element boundaries using the appropriate start- and end-tags for those elements. Each <!ELEMENT... declaration defines a class of elements that may or may not be used in a document conforming to that DTD. We call this class of elements an `element type' . Just as the HTML DTD includes the H1 and P element types, your document can have color and price element types.

Non-empty elements are made up of a start-tag, the element's content, and an end-tag. <color>red</color> is a complete instance of the color element. <color> is only the start-tag of the element, showing where it begins; it is not the element itself.

Empty elements are a special case that may be represented either as a pair of start- and end-tags with nothing between them (eg <price retail="123"></price>) or as a single empty element start-tag that has a closing slash to tell the parser `don't go looking for an end-tag to match this' (eg <price retail="123"/>). [Bob DuCharme]

This FAQ is from The XML FAQ, maintained by Peter Flynn