XML - Markup

The function of the markup in an XML document is to describe its structure:

• storage (physical)
• and logical structure (and to associate attribute name-value pairs with its logical structures).

Markup takes the form of:

• start-tags,
• end-tags,
• empty-element tags,
• entity references,
• character references,
• comments,
• CDATA section delimiters,
• document type declarations,
• processing instructions,
• XML declarations,
• text declarations,
• and any white space that is at the top level of the document entity (that is, outside the document element and not inside any other markup).