Status validating identity
The errata list for this fifth edition is available at A Test Suite is maintained to help assessing conformance to this specification.
This document has been reviewed by W3C Members, by software developers, and by other W3C groups and interested parties, and is endorsed by the Director as a W3C Recommendation.
Markup encodes a description of the document's storage layout and logical structure.
XML provides a mechanism to impose constraints on the storage layout and logical structure.
This document specifies a syntax created by subsetting an existing, widely used international text processing standard (Standard Generalized Markup Language, ISO 8886(E) as amended and corrected) for use on the World Wide Web.
It is a product of the XML Core Working Group as part of the XML Activity. As a convenience to readers, it incorporates the changes dictated by the accumulated errata (available at to the Fourth Edition of XML 1.0, dated 16 August 2006.
An individual who has actual knowledge of a patent which the individual believes contains Essential Claim(s) must disclose the information in accordance with section 6 of the W3C Patent Policy.
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.
W3C's role in making the Recommendation is to draw attention to the specification and to promote its widespread deployment.
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.
Most of the errata in the list provide a rationale for the change.
This version of the XML specification may be distributed freely, as long as all text and legal notices remain intact.
[Definition: A violation of the rules of this specification; results are undefined.