The Structure Module

The SMIL Structure module defines the basic structure of a SMIL 2.0 document. It is a mandatory module in all SMIL profiles.

As you saw in Listing 24.1, each SMIL document, or document fragment, is nested within a smil element. A smil element has a number of permitted attributes. The id attribute provides a way to uniquely identify the smil element. The class attribute is new in SMIL 2.0 and allows one or more class names to be assigned to the smil element. The xml:lang attribute defines the language of the content of the smil element. The title attribute provides a description of the element and might, optionally, be used by a user agent (such as the X-Smiles browser) to display the value of the title attribute. As in other XML elements, there is also an xmlns attribute.

The smil element is permitted to have only two elements as its child elements—the head element and the body element.

The head Element

The head element has content that is not related to the timing of a SMIL presentation. Thus, it might contain layout information, as you saw in Listing 24.1, meta information (typically contained in a meta element), or author-defined content control. For further information on content control in SMIL, see the “Content Control Modules” section later in this chapter.

The head element can possess id, title, class, and xml:lang attributes but not an xmlns attribute. The definitions for the four permitted attributes are the same as for the smil element.

The body Element

The body element can possess id, title, class, and xml:lang attributes but not an xmlns attribute. The definitions for the four permitted attributes are the same as for the smil element.

The body element contains elements that define the media objects to be used in a presentation and the timing of their use.