Learning XML

2.2. Elements: The Building Blocks of XML

Elements are parts of a document. You can separate a document into parts so they can be rendered differently, or used by a search engine. Elements can be containers, with a mixture of text and other elements. This element contains only text:

<flooby>This is text contained inside an element</flooby>

and this element contains both text and elements:

<outer>this is text<inner>more
text</inner>still more text</outer>

Some elements are empty, and contribute information by their position and attributes. There is an empty element inside this example:

<outer>an element can be empty: <nuttin/></outer>

Figure 2.7 shows the syntax for a container element. It begins with a start tag (1) consisting of an angle bracket (<) followed by a name (2). The start tag may contain some attributes (3) separated by whitespace, and it ends with a closing angle bracket (>). An attribute defines a property of the element and consists of a name (4) joined by an equals sign (=) to a value in quotes (5). An element can have any number of attributes, but no two attributes can have the same name. Following the start tag is the element's content (6), which in turn is followed by an end tag (7). The end tag consists of an opening angle bracket, a slash, the element's name, and a closing bracket. The end tag has no attributes, and the element name must match the start tag's name exactly.

Figure 2.7. Container element syntax

As shown in Figure 2.8, an empty element ...