XML规范英文版.docx

XML规范英文版.docx

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XML规范英文版

REC-xml-19980210

ExtensibleMarkupLanguage（XML）1.0

W3CRecommendation10-February-1998

Thisversion:

http:

//www.w3.org/TR/1998/REC-xml-19980210

http:

//www.w3.org/TR/1998/REC-xml-19980210.xml

http:

//www.w3.org/TR/1998/REC-xml-19980210.html

http:

//www.w3.org/TR/1998/REC-xml-19980210.pdf

http:

//www.w3.org/TR/1998/REC-xml-19980210.ps

Latestversion:

http:

//www.w3.org/TR/REC-xml

Previousversion:

http:

//www.w3.org/TR/PR-xml-971208

Editors:

TimBray（TextualityandNetscape）

JeanPaoli（Microsoft）

C.M.Sperberg-McQueen（UniversityofIllinoisatChicago）

Abstract

TheExtensibleMarkupLanguage（XML）isasubsetofSGMLthatiscompletelydescribedinthisdocument.ItsgoalistoenablegenericSGMLtobeserved,received,andprocessedontheWebinthewaythatisnowpossiblewithHTML.XMLhasbeendesignedforeaseofimplementationandforinteroperabilitywithbothSGMLandHTML.

Statusofthisdocument

ThisdocumenthasbeenreviewedbyW3CMembersandotherinterestedpartiesandhasbeenendorsedbytheDirectorasaW3CRecommendation.Itisastabledocumentandmaybeusedasreferencematerialorcitedasanormativereferencefromanotherdocument.W3C'sroleinmakingtheRecommendationistodrawattentiontothespecificationandtopromoteitswidespreaddeployment.ThisenhancesthefunctionalityandinteroperabilityoftheWeb.

Thisdocumentspecifiesasyntaxcreatedbysubsettinganexisting,widelyusedinternationaltextprocessingstandard（StandardGeneralizedMarkupLanguage,ISO8879:

1986（E）asamendedandcorrected）foruseontheWorldWideWeb.ItisaproductoftheW3CXMLActivity,detailsofwhichcanbefoundathttp:

//www.w3.org/XML.AlistofcurrentW3CRecommendationsandothertechnicaldocumentscanbefoundathttp:

//www.w3.org/TR.

ThisspecificationusesthetermURI,whichisdefinedby[Berners-Leeetal.],aworkinprogressexpectedtoupdate[IETFRFC1738]and[IETFRFC1808].

Thelistofknownerrorsinthisspecificationisavailableathttp:

//www.w3.org/XML/xml-19980210-errata.

Pleasereporterrorsinthisdocumenttoxml-editor@w3.org.

ExtensibleMarkupLanguage（XML）1.0

TableofContents

1.Introduction

    1.1OriginandGoals

    1.2Terminology

2.Documents

    2.1Well-FormedXMLDocuments

    2.2Characters

    2.3CommonSyntacticConstructs

    2.4CharacterDataandMarkup

    2.5Comments

    2.6ProcessingInstructions

    2.7CDATASections

    2.8PrologandDocumentTypeDeclaration

    2.9StandaloneDocumentDeclaration

    2.10WhiteSpaceHandling

    2.11End-of-LineHandling

    2.12LanguageIdentification

3.LogicalStructures

    3.1Start-Tags,End-Tags,andEmpty-ElementTags

    3.2ElementTypeDeclarations

        3.2.1ElementContent

        3.2.2MixedContent

    3.3Attribute-ListDeclarations

        3.3.1AttributeTypes

        3.3.2AttributeDefaults

        3.3.3Attribute-ValueNormalization

    3.4ConditionalSections

4.PhysicalStructures

    4.1CharacterandEntityReferences

    4.2EntityDeclarations

        4.2.1InternalEntities

        4.2.2ExternalEntities

    4.3ParsedEntities

        4.3.1TheTextDeclaration

        4.3.2Well-FormedParsedEntities

        4.3.3CharacterEncodinginEntities

    4.4XMLProcessorTreatmentofEntitiesandReferences

        4.4.1NotRecognized

        4.4.2Included

        4.4.3IncludedIfValidating

        4.4.4Forbidden

        4.4.5IncludedinLiteral

        4.4.6Notify

        4.4.7Bypassed

        4.4.8IncludedasPE

    4.5ConstructionofInternalEntityReplacementText

    4.6PredefinedEntities

    4.7NotationDeclarations

    4.8DocumentEntity

5.Conformance

    5.1ValidatingandNon-ValidatingProcessors

    5.2UsingXMLProcessors

6.Notation

Appendices

A.References

    A.1NormativeReferences

    A.2OtherReferences

B.CharacterClasses

C.XMLandSGML（Non-Normative）

D.ExpansionofEntityandCharacterReferences（Non-Normative）

E.DeterministicContentModels（Non-Normative）

F.AutodetectionofCharacterEncodings（Non-Normative）

G.W3CXMLWorkingGroup（Non-Normative）

1.Introduction

ExtensibleMarkupLanguage,abbreviatedXML,describesaclassofdataobjectscalledXMLdocumentsandpartiallydescribesthebehaviorofcomputerprogramswhichprocessthem.XMLisanapplicationprofileorrestrictedformofSGML,theStandardGeneralizedMarkupLanguage[ISO8879].Byconstruction,XMLdocumentsareconformingSGMLdocuments.

XMLdocumentsaremadeupofstorageunitscalledentities,whichcontaineitherparsedorunparseddata.Parseddataismadeupofcharacters,someofwhichformcharacterdata,andsomeofwhichformmarkup.Markupencodesadescriptionofthedocument'sstoragelayoutandlogicalstructure.XMLprovidesamechanismtoimposeconstraintsonthestoragelayoutandlogicalstructure.

AsoftwaremodulecalledanXMLprocessorisusedtoreadXMLdocumentsandprovideaccesstotheircontentandstructure.ItisassumedthatanXMLprocessorisdoingitsworkonbehalfofanothermodule,calledtheapplication.ThisspecificationdescribestherequiredbehaviorofanXMLprocessorintermsofhowitmustreadXMLdataandtheinformationitmustprovidetotheapplication.

1.1OriginandGoals

XMLwasdevelopedbyanXMLWorkingGroup（originallyknownastheSGMLEditorialReviewBoard）formedundertheauspicesoftheWorldWideWebConsortium（W3C）in1996.ItwaschairedbyJonBosakofSunMicrosystemswiththeactiveparticipationofanXMLSpecialInterestGroup（previouslyknownastheSGMLWorkingGroup）alsoorganizedbytheW3C.ThemembershipoftheXMLWorkingGroupisgiveninanappendix.DanConnollyservedastheWG'scontactwiththeW3C.

ThedesigngoalsforXMLare:

1.XMLshallbestraightforwardlyusableovertheInternet.

2.XMLshallsupportawidevarietyofapplications.

3.XMLshallbecompatiblewithSGML.

4.ItshallbeeasytowriteprogramswhichprocessXMLdocuments.

5.ThenumberofoptionalfeaturesinXMListobekepttotheabsoluteminimum,ideallyzero.

6.XMLdocumentsshouldbehuman-legibleandreasonablyclear.

7.TheXMLdesignshouldbepreparedquickly.

8.ThedesignofXMLshallbeformalandconcise.

9.XMLdocumentsshallbeeasytocreate.

10.TersenessinXMLmarkupisofminimalimportance.

Thisspecification,togetherwithassociatedstandards（UnicodeandISO/IEC10646forcharacters,InternetRFC1766forlanguageidentificationtags,ISO639forlanguagenamecodes,andISO3166forcountrynamecodes）,providesalltheinformationnecessarytounderstandXMLVersion1.0andconstructcomputerprogramstoprocessit.

ThisversionoftheXMLspecificationmaybedistributedfreely,aslongasalltextandlegalnoticesremainintact.

1.2Terminology

TheterminologyusedtodescribeXMLdocumentsisdefinedinthebodyofthisspecification.ThetermsdefinedinthefollowinglistareusedinbuildingthosedefinitionsandindescribingtheactionsofanXMLprocessor:

may

ConformingdocumentsandXMLprocessorsarepermittedtobutneednotbehaveasdescribed.

must

ConformingdocumentsandXMLprocessorsarerequiredtobehaveasdescribed;otherwisetheyareinerror.

error

Aviolationoftherulesofthisspecification;resultsareundefined.Conformingsoftwaremaydetectandreportanerrorandmayrecoverfromit.

fatalerror

AnerrorwhichaconformingXMLprocessormustdetectandreporttotheapplication.Afterencounteringafatalerror,theprocessormaycontinueprocessingthedatatosearchforfurthererrorsandmayreportsucherrorstotheapplication.Inordertosupportcorrectionoferrors,theprocessormaymakeunprocesseddatafromthedocument（withintermingledcharacterdataandmarkup）availabletotheapplication.Onceafatalerrorisdetected,however,theprocessormustnotcontinuenormalprocessing（i.e.,itmustnotcontinuetopasscharacterdataandinformationaboutthedocument'slogicalstructuretotheapplicationinthenormalway）.

atuseroption

Conformingsoftwaremayormust（dependingonthemodalverbinthesentence）behaveasdescribed;ifitdoes,itmustprovideusersameanstoenableordisablethebehaviordescribed.

validityconstraint

ArulewhichappliestoallvalidXMLdocuments.Violationsofvalidityconstraintsareerrors;theymust,atuseroption,bereportedbyvalidatingXMLprocessors.

well-formednessconstraint

Arulewhichappliestoallwell-formedXMLdocuments.Violationsofwell-formednessconstraintsarefatalerrors.

match

（Ofstringsornames:

）Twostringsornamesbeingcomparedmustbeidentical.CharacterswithmultiplepossiblerepresentationsinISO/IEC10646（e.g.characterswithbothprecomposedandbase+diacriticforms）matchonlyiftheyhavethesamerepresentationinbothstrings.Atuseroption,processorsmaynormalizesuchcharacterstosomecanonicalform.Nocasefoldingisperformed.（Ofstringsandrulesinthegrammar:

）Astringmatchesagrammaticalproductionifitbelongstothelanguagegeneratedbythatproduction.（Ofcontentandcontentmodels:

）Anelementmatchesitsdeclarationwhenitconformsinthefashiondescribedintheconstraint"ElementValid".

forcompatibility

AfeatureofXMLincludedsolelytoensurethatXMLremainscompatiblewithSGML.

forinteroperability

Anon-bindingrecommendationincludedtoincreasethechancesthatXMLdocumentscanbeprocessedbytheexistinginstalledbaseofSGMLprocessorswhichpredatetheWebSGMLAdaptationsAnnextoISO8879.

2.Documents

AdataobjectisanXMLdocumentifitiswell-formed,asdefinedinthisspecification.Awell-formedXMLdoc