XML Infoset Element Children Property Explained

This article provides an overview of the [children] property of an element information item within the W3C XML Information Set (Infoset) specification. It defines what the [children] property is, details the specific types of information items it contains, explains how document order is preserved, and highlights important distinctions regarding what is excluded from this list.

Definition of the [children] Property

In the W3C XML Information Set standard, an XML document is modeled as an abstract tree of “information items.” An element information item represents an XML element within the document. The [children] property of an element information item is an ordered list containing all the information items that appear directly inside that element’s opening and closing tags.

Items Included in the [children] List

The [children] property maintains document order and can include the following types of information items:

• Element Information Items: Any child elements nested directly within the parent element.
• Character Information Items: Every character of text content contained directly within the element, including whitespace, unless stripped by an application.
• Comment Information Items: Any XML comments (<!-- ... -->) appearing directly inside the element.
• Processing Instruction Information Items: Any processing instructions (<?target ...?>) contained directly within the element.
• Unexpanded Entity Reference Information Items: References to external or unparsed entities that were not expanded during processing.

If an element is empty (such as <example/> or <example></example>), its [children] property contains an empty list.

Items Excluded from the [children] List

Certain components of an XML element are handled via distinct properties rather than the [children] property:

• Attributes: Attributes do not appear in the [children] list. Instead, they are represented in the [attributes] property as an unordered set of attribute information items.
• Namespace Declarations: Namespaces are recorded separately in properties such as [in-scope namespaces] and [namespace attributes].
• Document-Level Declarations: The XML declaration and Document Type Definition (DTD) reside outside element content and are associated with the document information item.