1 Introduction 1.1 Origin and Goals 1.2 Terminology 2 Documents 2.1 Well-Formed XML Documents 2.2 Characters 2.3 Common Syntactic Constructs 2.4 Character Data and Markup 2.5 Comments 2.6 Processing Instructions 2.7 CDATA Sections 2.8 Prolog and Document Type Declaration 2.9 Standalone Document Declaration 2.10 White Space Handling 2.11 End-of-Line Handling 2.12 Language Identification 3 Logical Structures 3.1 Start-Tags, End-Tags, and Empty-Element Tags 3.2 Element Type Declarations 3.2.1 Element Content 3.2.2 Mixed Content 3.3 Attribute-List Declarations 3.3.1 Attribute Types 3.3.2 Attribute Defaults 3.3.3 Attribute-Value Normalization 3.4 Conditional Sections 4 Physical Structures 4.1 Character and Entity References 4.2 Entity Declarations 4.2.1 Internal Entities 4.2.2 External Entities 4.3 Parsed Entities 4.3.1 The Text Declaration 4.3.2 Well-Formed Parsed Entities 4.3.3 Character Encoding in Entities 4.4 XML Processor Treatment of Entities and References 4.4.1 Not Recognized 4.4.2 Included 4.4.3 Included If Validating 4.4.4 Forbidden 4.4.5 Included in Literal 4.4.6 Notify 4.4.7 Bypassed 4.4.8 Included as PE 4.4.9 Error 4.5 Construction of Entity Replacement Text 4.6 Predefined Entities 4.7 Notation Declarations 4.8 Document Entity 5 Conformance 5.1 Validating and Non-Validating Processors 5.2 Using XML Processors 6 Notation A References A.1 Normative References A.2 Other References B Character Classes C XML and SGML (Non-Normative) D Expansion of Entity and Character References (Non-Normative) E Deterministic Content Models (Non-Normative) F Autodetection of Character Encodings (Non-Normative) F.1 Detection Without External Encoding Information F.2 Priorities in the Presence of External Encoding Information G W3C XML Working Group (Non-Normative) H W3C XML Core Working Group (Non-Normative) I Production Notes (Non-Normative) J Suggestions for XML Names (Non-Normative) Extensible Markup Language, abbreviated XML, describes a class of data objects called XML documents and partially describes the behavior of computer programs which process them.XML is an application profile or restricted form of SGML, the Standard Generalized Markup Language [ISO 8879].Most of the errata in the list provide a rationale for the change.The errata list for this fifth edition is available at A Test Suite is maintained to help assessing conformance to this specification.Please report errors in this document to the public [email protected] list; public archives are available.For the convenience of readers, an XHTML version with color-coded revision indicators is also provided; this version highlights each change due to an erratum published in the errata list for the previous edition, together with a link to the particular erratum in that list.
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By construction, XML documents are conforming SGML documents.
XML documents are made up of storage units called entities, which contain either parsed or unparsed data.
W3C's role in making the Recommendation is to draw attention to the specification and to promote its widespread deployment.
This enhances the functionality and interoperability of the Web.