Each element type declaration generally describes three parts: a start tag, content, and an end tag.

The element's name appears in the start tag (written ) and the end tag (written ); note the slash before the element name in the end tag. For example, the start and end tags of the element type delimit the items in a list:

<sapi:author>     <sapi:name>Dmitry Sheiko</sapi:name>     <sapi:email>sheiko@cmsdevelopment.com</sapi:email>     <sapi:uri>www.cmsdevelopment.com</sapi:uri> </sapi:author>

Some SAPI element types have no content (SAPI:VALUE-OF, SAPI:SQL, etc.). Such element types should be defined in the syntax of the «empty element tag» (for reference see also Extensible Markup Language (XML). W3C Recommendation 04: Start-Tags, End-Tags, and Empty-Element Tags):

<sapi:value-of name="var1.value " />

Correctness restrictions: Unique attribute specification

An attribute name cannot be used more than once within one start tag (or an empty element tag).

Correctness restrictions: Absence of character < in attribute values

Characters < and > are not allowed in attribute values.

All element types mentioned in this specification are listed in the Elements Reference.