EPUB Content Documents 3.0.1
EPUB Content Documents 3.0.1
Recommended Specification
26 June 2014
This version
Latest version
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from the previous version is also available.
Please refer to the
errata
for this document, which may include some normative corrections.
Copyright © 2010-2013 International Digital Publishing Forum™
All rights reserved. This work is protected under Title 17 of the United States Code. Reproduction and dissemination of this work with changes is prohibited except with the written permission of the
International Digital Publishing Forum (IDPF)
EPUB is a registered trademark of the International Digital Publishing Forum.
Editors
Markus Gylling, International Digital Publishing Forum (IDPF)
William McCoy, International Digital Publishing Forum (IDPF)
Elika J. Etemad, Invited Expert
Matt Garrish, Invited Expert
Table of Contents
1. Overview
1.1. Purpose and Scope
1.2. Relationship to Other Specifications
1.2.1. Relationship to HTML5
1.2.2. Relationship to SVG
1.2.3. Relationship to CSS
1.2.4. Future Maintenance
1.3. Terminology
1.4. Typographic Conventions
1.5. Conformance Statements
1.6. Namespace prefix mappings
2. EPUB Content Documents
2.1. XHTML Content Documents
2.1.1. Content Conformance
2.1.2. Reading System Conformance
2.1.3. HTML5 Extensions
2.1.3.1. Semantic Markup
2.1.3.1.1. Semantic Inflection
2.1.3.1.1.1. Introduction
2.1.3.1.1.2. The
epub:type
Attribute
2.1.3.1.1.3. Vocabulary Association
2.1.3.1.1.4. Processing Requirements
2.1.3.1.2. Semantic Enrichment
2.1.3.1.2.1. Introduction
2.1.3.1.2.2. Content Conformance
2.1.3.1.2.3. Processing Requirements
2.1.3.2. SSML Attributes
2.1.3.2.1. Overview
2.1.3.2.2. The
ssml:ph
attribute
2.1.3.2.3. The
ssml:alphabet
attribute
2.1.3.3. Content Switching
2.1.3.3.1. Introduction
2.1.3.3.2. Definition
2.1.3.3.2.1. The
epub:switch
Element
2.1.3.3.2.2. The
epub:case
Element
2.1.3.3.2.3. The
epub:default
Element
2.1.3.3.3. Processing
2.1.3.4. The
epub:trigger
Element
2.1.3.5. Alternate Style Tags
2.1.3.6. Custom Attributes
2.1.3.7. The
aria-describedat
Attribute
2.1.4. HTML5 Deviations and Constraints
2.1.4.1. Embedded MathML
2.1.4.1.1. Introduction
2.1.4.1.2. Content Conformance
2.1.4.1.3. Reading System Conformance
2.1.4.1.4. Alternative Content
2.1.4.2. Embedded SVG
2.1.4.2.1. Embedded SVG and CSS
2.1.4.3. Unicode Restrictions
2.1.4.4. Discouraged Constructs
2.1.4.5. Special Considerations
2.1.4.5.1. The
body
element
2.2. EPUB Navigation Documents
2.2.1. Introduction
2.2.2. Content Conformance
2.2.3. Reading System Conformance
2.2.4. EPUB Navigation Document Definition
2.2.4.1. The
nav
Element: Restrictions
2.2.4.2. The
nav
Element: Types
2.2.4.2.1. The
toc
nav
Element
2.2.4.2.2. The
page-list
nav
Element
2.2.4.2.3. The
landmarks
nav
Element
2.2.4.2.4. Other
nav
Elements
2.2.4.3. The
hidden
attribute
2.3. SVG Content Documents
2.3.1. Introduction
2.3.2. Content Conformance
2.3.3. Restrictions on SVG 1.1
2.3.4. Reading System Conformance
2.3.5. Semantic Inflection
2.4. Scripted Content Documents
2.4.1. Scripting Contexts
2.4.2. Content Conformance
2.4.3. Reading System Conformance
2.4.4. Security Considerations
2.4.5. Event Model Considerations
2.5. Fixed-Layout Documents
2.5.1. Introduction
2.5.2. Reading System Conformance
2.5.3. Viewport Rendering
2.5.4. Content Dimensions for XHTML and SVG
2.5.4.1. Expressing ICB Dimensions in XHTML
2.5.4.2. Expressing ICB Dimensions in SVG
3. EPUB Style Sheets
3.1. Content Conformance
3.2. Reading System Conformance
3.3. EPUB 3 CSS Profile
3.3.1. CSS 2.1
3.3.2. CSS 2.0
3.3.3. CSS 3.0 Speech
3.3.4. CSS Fonts Level 3
3.3.5. CSS Text Level 3
3.3.6. CSS Text Decoration Level 3
3.3.7. CSS Writing Modes
3.3.8. Selectors
3.3.9. Media Queries
3.3.10. CSS Namespaces
3.3.11. CSS Multi-Column Layout
3.3.12. Ruby Positioning
3.3.13. Display Property Values
oeb-page-head
and
oeb-page-foot
[DEPRECATED]
4. PLS Documents
4.1. Overview
4.2. EPUB Publication Conformance
4.3. Content Conformance
4.4. Reading System Conformance
A. JavaScript epubReadingSystem Object
A.1. Syntax
A.2. Description
A.3. Properties
A.4. Methods
A.4.1. hasFeature
A.4.1.1. Syntax
A.4.1.2. Description
A.4.1.3. Features
B.
-epub-fullsize-kana
Character Mapping Reference
C. Acknowledgements and Contributors
References
1 Overview
1.1 Purpose and Scope
This section is informative
This specification, EPUB Content Documents 3.0.1, defines profiles of HTML5, SVG, and CSS for use in the context of
EPUB® Publications
This specification is one of a family of related specifications that compose EPUB 3, the third major revision of an interchange and delivery format for digital publications based on XML and Web Standards. It is meant to be read and understood in concert with the other specifications that make up EPUB 3:
The EPUB 3 Overview
EPUB3Overview
, which provides an informative overview of EPUB and a roadmap to the rest of the EPUB 3 documents. The Overview should be read first.
EPUB Publications 3.0.1
Publications301
, which defines the semantics and overarching conformance requirements for each
Rendition
of an
EPUB Publication
EPUB Open Container Format (OCF) 3.0.1
OCF301
, which defines a file format and processing model for encapsulating a set of related resources into a single-file (ZIP)
EPUB Container
EPUB Media Overlays 3.0.1
MediaOverlays301
, which defines a format and a processing model for synchronization of text and audio.
This specification supersedes EPUB Content Documents 3.0
ContentDocs30
. Refer to
EPUB3Changes
for information on differences between this specification and its predecessor.
1.2 Relationship to Other Specifications
This section is informative
1.2.1 Relationship to HTML5
The
XHTML document type defined by this specification
is based on W3C
HTML5
, and inherits all definitions of semantics, structure and processing behaviors from the HTML5 specification unless otherwise specified.
In addition, this specification
defines a set of extensions
to the W3C HTML5 document model that
Author
s may include in
XHTML Content Document
s.
This specification defines a simplified processing model that does not require Reading Systems to support scripting, HTML5 forms or the HTML5 DOM.
EPUB Reading System
s conformant with this specification are only required to be able to process a conforming
EPUB Content Document
. As
support for scripting and HTML5 forms
are optional Reading System features, a conformant Reading System might not be a fully-conformant HTML5 User Agent (i.e., it might not implement the complete HTML5 processing model).
1.2.2 Relationship to SVG
This specification defines
a restricted subset of SVG 1.1
to represent vector graphics inline in
XHTML Content Document
s and as standalone
SVG Content Document
s.
1.2.3 Relationship to CSS
The
CSS profile
defined in this specification has CSS 2.1
CSS2.1
as its baseline. Any CSS Style Sheet that conforms to CSS 2.1 may be used in the context of an EPUB Publication, except as noted in
CSS 2.1
This specification also incorporates features defined by CSS3 Modules and introduces EPUB-specific CSS constructs.
1.2.4 Future Maintenance
This specification references W3C specifications that are not yet final, and incompatible changes to them may occur in the future that would cause EPUB 3 Content Documents that were previously conformant to no longer be conformant to the latest versions of the referenced specifications.
The IDPF anticipates revising this specification if and when such incompatible changes occur, updating the normative constraints defined herein as necessary.
1.3 Terminology
EPUB Publication
A collection of one or more
Rendition
s conforming to
this specification and its
sibling specifications
, packaged in an
EPUB Container
An EPUB Publication typically represents a single intellectual or artistic work, but
this specification and its
sibling specifications
do not circumscribe the nature of the content.
Rendition
A logical document entity consisting of a set of interrelated
resources
representing one rendering of an
EPUB Publication
Publication Resource
A resource that contains content or instructions that contribute to the logic and rendering of at least one
Rendition
of an
EPUB Publication
. In the absence of this resource, the EPUB Publication might not render as intended by the
Author
. Examples of Publication Resources include a Rendition's
Package Document
EPUB Content Document
EPUB Style Sheet
s, audio, video, images, embedded fonts and scripts.
With the exception of the Package Document itself, the Publication Resources required to render a Rendition are listed in that Rendition's
manifest
Publications301
and bundled in the
EPUB Container
file (unless specified otherwise in
Publication Resource Locations
Publications301
).
Examples of resources that are not Publication Resources include those identified by the Package Document
link
Publications301
element and those identified in outbound hyperlinks that resolve outside the
EPUB Container
(e.g., referenced from an
HTML5
element
href
attribute).
Core Media Type Resource
Publication Resource
that is a
Core Media Type
and may therefore be included in the
EPUB Publication
without the provision of
fallbacks
Publications301
EPUB Content Document
Publication Resource
that conforms to one of the EPUB Content Document definitions (
XHTML
or
SVG
).
An EPUB Content Document is a
Core Media Type
, and may therefore be included in the
EPUB Publication
without the provision of
fallbacks
Publications301
XHTML Content Document
An
EPUB Content Document
conforming to the profile of
HTML5
defined in
XHTML Content Documents
XHTML Content Documents use the
XHTML syntax
of
HTML5
SVG Content Document
An
EPUB Content Document
conforming to the constraints expressed in
SVG Content Documents
EPUB Navigation Document
A specialization of the
XHTML Content Document
, containing human- and machine-readable global navigation information, conforming to the constraints expressed in
EPUB Navigation Documents
Scripted Content Document
An
EPUB Content Document
that includes scripting or an
XHTML Content Document
that contains
HTML5 forms
elements.
Refer to
Scripted Content Documents
for more information.
Top-level Content Document
An
EPUB Content Document
referenced from the
spine
, whether directly or via a
fallback chain
Publications301
Fixed-Layout Document
An
EPUB Content Document
directly referenced from the spine that has been designated
pre-paginated
in the
Package Document
, as defined in
The rendition:layout Property
Publications301
The dimensions to use for rendering Fixed-Layout Documents are defined in
Fixed-Layout Documents
ContentDocs301
Core Media Type
A set of
Publication Resource
types for which no fallback is required. Refer to
Publication Resources
Publications301
for more information.
Package Document
Publication Resource
carrying bibliographical and structural metadata about a given
Rendition
of an
EPUB Publication
, as defined in
Package Documents
Publications301
Manifest
A list of all
Publication Resource
s that constitute the given
Rendition
of a
EPUB Publication
Refer to
manifest
Publications301
for more information.
Spine
An ordered list of
Publication Resource
s,
typically
EPUB Content Document
s, representing the default reading order of the given
Rendition
of an EPUB Publication.
Refer to
spine
Publications301
for more information.
Text-to-Speech (TTS)
The rendering of the textual content of an
EPUB Publication
as artificial human speech using a synthesized voice.
EPUB Style Sheet (or Style Sheet)
A CSS Style Sheet conforming to the CSS profile defined in
EPUB Style Sheets
Viewport
The region of an
EPUB Reading System
in which the content of an
EPUB Publication
is rendered visually to a
User
CSS Viewport
Viewport
capable of displaying CSS-styled content.
SVG Viewport
Viewport
capable of displaying SVG images.
EPUB Container (or Container)
The ZIP-based packaging and distribution format for
EPUB Publication
s defined in
OCF301
Author
The person(s) or organization responsible for the creation of an
EPUB Publication
, which is not necessarily the creator of the content and resources it contains.
User
An individual that consumes an
EPUB Publication
using an
EPUB Reading System
EPUB Reading System (or Reading System)
A system that processes
EPUB Publication
s for presentation to a
User
in a manner conformant with
this specification and its
sibling specifications
1.4 Typographic Conventions
The following typographic conventions are used in this specification:
markup
All markup (elements, attributes, properties), code (JavaScript, pseudo-code), machine processable values (string, characters, media types) and file names are in red-orange monospace font.
markup
Links to markup and code definitions are underlined and in red-orange monospace font. Only the first instance in each section is linked.
URIs are in navy blue monospace font.
hyperlink
Hyperlinks are underlined and in blue.
[reference]
Normative and informative references are enclosed in square brackets.
Term
Terms defined in the
Terminology
are in capital case.
Term
Links to term definitions have a dotted blue underline. Only the first instance in each section is linked.
Normative element, attribute and property definitions are in blue boxes.
Informative markup examples are in white boxes.
note
Informative notes are in yellow boxes with a "Note" header.
caution
Informative cautionary note are in red boxes with a "Caution" header.
1.5 Conformance Statements
The keywords
MUST
MUST NOT
REQUIRED
SHALL
SHALL NOT
SHOULD
SHOULD NOT
RECOMMENDED
MAY
, and
OPTIONAL
in this document are to be interpreted as described in
RFC2119
All sections of this specification are normative except where identified by the informative status label "This section is informative". The application of informative status to sections and appendices applies to all child content and subsections they may contain.
All examples in this specification are informative.
1.6 Namespace prefix mappings
For convenience, the following namespace prefix mappings
XMLNS
are used throughout this specification:
prefix
namespace URI
epub
pls
ssml
svg
2 EPUB Content Documents
2.1 XHTML Content Documents
This section defines a profile of
HTML5
for creating XHTML Content Documents. An instance of an XML document that conforms to this profile is a
Core Media Type
and is referred to in this specification and its
sibling specifications
as an
XHTML Content Document
Unless otherwise specified, this specification inherits all definitions of semantics, structure and processing behaviors from the
HTML5
specification.
caution
The EPUB 3 XHTML Content Document definition references features in the W3C
HTML5
specification that are still works in progress and may change in incompatible ways. When utilizing such features, authors should consider the inherent risks in terms of the potential impact on interoperability and document longevity.
2.1.1 Content Conformance
An
XHTML Content Document
must
meet all of the following criteria:
Document Properties
It
must
meet the conformance constraints for XML documents defined in
XML Conformance
Publications301
It
must
be an
HTML5
document that conforms to the
XHTML syntax
For all document constructs used that are defined by
HTML5
, it
must
conform to the conformance criteria defined for those constructs in that specification, unless explicitly overridden in
HTML5 Deviations and Constraints
It
may
include extensions to the
HTML5
grammar as defined in
HTML5 Extensions
, and
must
conform to all content conformance constraints defined therein.
File Properties
The XHTML Content Document filename
should
use the file extension
.xhtml
note
All
Publication Resource
s referenced from an XHTML Content Document must conform to the constraints for Publication Resources defined in
EPUB Publication — Content Conformance
Publications301
2.1.2 Reading System Conformance
A conformant
EPUB Reading System
must
meet all of the following criteria for processing
XHTML Content Document
s:
Unless explicitly defined by this specification or its
sibling specifications
as overridden, it
must
process XHTML Content Documents using semantics defined by the
HTML5
specification and honor any applicable User Agent conformance constraints expressed therein.
It
must
meet all Reading System conformance criteria defined in
HTML5 Extensions
It
must
recognize and adapt behaviorally to the constraints defined in
HTML5 Deviations and Constraints
It
must
meet the Reading System conformance criteria defined in
Scripted Content Documents — Reading System Conformance
It
must
support visual rendering of XHTML Content Documents as defined in
EPUB Style Sheets — Reading System Conformance
It
should
recognize embedded ARIA markup and support exposure of any given ARIA roles, states and properties to platform accessibility APIs
WAI-ARIA
2.1.3 HTML5 Extensions
This section defines EPUB 3
XHTML Content Document
extensions to the underlying
HTML5
document model.
2.1.3.1 Semantic Markup
2.1.3.1.1 Semantic Inflection
2.1.3.1.1.1 Introduction
This section is informative
Semantic inflection is the process of attaching additional meaning about the specific purpose and/or nature an element plays in an
XHTML Content Document
. In the context of
EPUB Publication
s, the
epub:type
attribute is typically used to express domain-specific semantics, with the inflection(s) it carries complementing the underlying
HTML5
host vocabulary. The applied semantics always refine the meaning of their containing elements, never override their nature (e.g., the attribute can be used to indicate a
section
is a chapter in a work, but cannot be used to turn
elements into list items to avoid proper list structures).
Semantic metadata is not intended for human consumption; it instead provides a controlled way for Reading Systems and other User Agents to learn more about the structure and content of a document, providing them the opportunity to enhance the reading experience for Users.
This specification defines a method for semantic inflection using
the attribute axis
: instead of adding new XML elements to the XHTML Content Document vocabulary, the
epub:type
attribute can be appended to existing elements to inflect the desired semantics. A mechanism to identify external vocabularies that provide controlled values for the attributes is also defined.
2.1.3.1.1.2 The
epub:type
Attribute
The
epub:type
attribute inflects semantics on the element on which it appears. Its value is one or more space-separated terms stemming from external vocabularies associated with the document instance, as defined in
Vocabulary Association
The inflected semantic
must
express a subclass of the semantic of the carrying element. In the case of semantically neutral elements (such as
HTML5
div
and
span
), the inflected semantic
must not
attach a meaning that is already conveyed by an existing element (e.g., that a
div
represents a paragraph or section). Reading Systems
must
ignore inflected semantics
that conflict with the carrying element.
As the
HTML5
head
element is a metadata container for a document, structural semantics expressed on this element or any descendant of it have no meaning. Reading Systems
must
ignore such semantics.
note
The
epub:type
attribute is intended to be functionally equivalent to the W3C Role Attribute
Role
, but with restrictions as specified in
Vocabulary Association
. The IDPF's intent is to harmonize this attribute with W3C mechanisms for semantic inflection in a future major revision of the specification.
Attribute Name
type
Namespace
Usage
Global attribute
May
be specified on all elements.
Value
A space-separated list of
property
Publications301
values, with restrictions as defined in
Vocabulary Association
2.1.3.1.1.3 Vocabulary Association
This specification adopts the vocabulary association mechanisms defined in
Vocabulary Association Mechanisms
Publications301
, with the following modifications:
Default Vocabulary
The default vocabulary for Content Documents is defined to be the
EPUB 3 Structural Semantics Vocabulary
Reserved Prefixes
This specification reserves prefixes that Authors
may
use in the
epub:type
attribute in the normative document
EPUB Content Documents Reserved Prefixes
The
prefix
Attribute
The
prefix
attribute definition is unchanged, but the attribute is defined to be in the namespace
when used in EPUB Content Documents.
The
prefix
attribute is only valid on the
HTML5
root
html
element.
Examples
The following example shows the
epub:type
attribute used to inflect footnote and note reference semantics. The properties used are defined in the
default vocabulary

… 1 …




The following example shows the
epub:type
attribute used to inflect glossary semantics on an HTML5 definition list. The property used is defined in the
default vocabulary




The following example shows the
epub:type
attribute used to inflect source publication pagebreak semantics. The property used is defined in the
default vocabulary
. (Note that the
dc:source
Publications301
element provides a means of identifying the source publication to which the given pagination information applies.)

… …



2.1.3.1.1.4 Processing Requirements
A Reading System
must
process the
epub:type
attribute as follows:
It
may
associate specialized behaviors with none, some or all of the terms defined in the
default vocabulary
It
may
associate specialized behaviors with terms given in vocabularies other than the default.
It
must
ignore terms that it does not recognize.
When Reading System behavior associated with a given
epub:type
value conflicts with behavior associated with the carrying element, the behavior associated with the element
must
be given precedence.
2.1.3.1.2 Semantic Enrichment
2.1.3.1.2.1 Introduction
This section is informative
Unlike
semantic inflection
, which is about refining the structures within your markup, semantic enrichment enables the layering of meaning into the content in order to facilitate machine processing.
The
Microdata
and
RDFa11
specifications both define sets of attributes that can be used in
XHTML Content Document
s to semantically enrich the content.
2.1.3.1.2.2 Content Conformance
A conformant
XHTML Content Document
must
meet all of the following criteria:
It
must
allow the use of
Microdata
attributes as defined in that specification.
It
must
allow the use of
RDFa11
attributes as defined in
HTML+RDFa11
2.1.3.1.2.3 Processing Requirements
Reading Systems
may
process
Microdata
and
RDFa11
attributes as defined in their respective specifications, but such support is
optional
2.1.3.2 SSML Attributes
2.1.3.2.1 Overview
The W3C Speech Synthesis Markup Language
SSML
is a language used for assisting
Text-to-Speech (TTS)
engines in generating synthetic speech. Although SSML is designed as a standalone document type, it also defines semantics suitable for use within other host languages.
This specification recasts the
SSML 1.1
phoneme
element
as two attributes —
ssml:ph
and
ssml:alphabet
— and makes them available within EPUB XHTML Content Documents.
Reading Systems with
Text-to-Speech (TTS)
capabilities
should
support the SSML Attributes as defined below.
note
For more information on EPUB 3 features related to synthetic speech, refer to
Text-to-speech
EPUB3Overview
2.1.3.2.2 The
ssml:ph
attribute
The
ssml:ph
attribute specifies a phonemic/phonetic pronunciation of the text represented by the element to which the attribute is attached.
Attribute Name
ph
Namespace
Usage
Global attribute
. May be specified on all elements with which a phonetic equivalent can logically be associated (e.g., elements that contain textual information).
Must not be specified on a descendant of an element that already carries this attribute.
Value
A phonemic/phonetic expression, syntactically valid with respect to
the phonemic/phonetic alphabet being used
This attribute inherits all the semantics of the
SSML 1.1
phoneme
element
ph
attribute, with the following addition:
When the
ssml:ph
attribute appears on an element that has text node descendants, the corresponding document text to which the pronunciation applies is the string that results from concatenating the descendant text nodes, in document order. The specified phonetic pronunciation
must
therefore logically match the element's textual data in its entirety (i.e., not just an isolated part of its content).
note
Reading Systems that support the SSML Attributes and
PLS Documents
must honor the defined
precedence rules
for these two constructs.
2.1.3.2.3 The
ssml:alphabet
attribute
The
ssml:alphabet
attribute specifies which phonemic/phonetic pronunciation alphabet is used in the value of the
ssml:ph
attribute.
Attribute Name
alphabet
Namespace
Usage
Global attribute
May
be specified on any element.
Value
The name of the pronunciation alphabet used in the value of
ssml:ph
(inherited).
This attribute inherits all the semantics of the
SSML 1.1
phoneme
element
alphabet
attribute, with the following addition:
The value of the
ssml:alphabet
attribute is inherited in the document tree. The pronunciation alphabet used in a given
ssml:ph
attribute value is determined by locating the first occurrence of the
ssml:alphabet
attribute starting with the element on which the
ssml:ph
attribute appears, followed by the nearest ancestor element.
Reading Systems that support the
SSML Attributes
feature of this specification
should
support the IPA alphabet
[refIPA]
, as expressed by the value "
ipa
".
2.1.3.3 Content Switching
2.1.3.3.1 Introduction
This section is informative
The
switch
element provides a simple mechanism through which
Author
s can tailor the content displayed to Users, one that isn't dependent on the scripting capabilities of the
EPUB Reading System
Reading System developers may choose to support XML vocabularies and new HTML elements that are not valid in
XHTML Content Document
s. The
switch
mechanism encourages this type of development and experimentation, but at the same time provides Authors who wish to take advantage of it the security of knowing that their content will still display on any compliant Reading System (i.e., it maintains the baseline requirement that all XHTML Content Documents be valid if none of the specialized markup is supported).
Content switching is not just about encouraging future development, however; it can also be used to create
EPUB Publication
s that maintain a level of compatibility with older Reading Systems unable to handle the new features of EPUB 3. For example, instances of MathML, now a native type, could be added using
switch
elements so that EPUB 2 Reading Systems could instead provide fallback images or text.
2.1.3.3.2 Definition
2.1.3.3.2.1 The
epub:switch
Element
The
switch
element allows an XML fragment to be conditionally inserted into the content model of an XHTML Content Document.
Element name
switch
Namespace
Usage
In
Flow
and
Inline
content. Repeatable.
Attributes
id
[optional]
The ID
XML
of this element, which
must
be unique within the document scope.
Content Model
In this order:
case
[1 or more]
default
[exactly 1]
A Reading System
must
individually process each
switch
element in a document to determine whether it can render any of the child
case
elements (as determined by the value of their
required-namespace
attributes).
For each
switch
encountered, the Reading System
should
render the content of the first
case
it supports, but is free to select from any of the available options. If the Reading System does not support the markup contained in any of the child
case
elements, it
must
render the contents of the
default
element.
The
HTML5
object
element
should
be used to embed custom (non-core) content types in XHTML Content Documents. Custom markup
should
be wrapped in a
switch
element only when the content it represents is an integral part of the document and depends on the context of the document to be properly processed.
The
switch
element is not intended to replace intrinsic fallback mechanisms, such as the
MATHML
alttext
attribute and the
SVG
title
and
desc
elements. Authors
should
always consider including intrinsic fallbacks, even when including a
switch
for Reading Systems with no support for the host grammar (e.g., to ensure accessibility).
Examples
An example of ChemML markup inserted using the
switch
element.








H2SO4



An example of adding MathML markup for compliance with EPUB 2 Reading Systems.




2
⁡
x


+
y
-
z



2x + y - z



2.1.3.3.2.2 The
epub:case
Element
The
case
element contains an instance of markup from an XML vocabulary. The included markup
may
be natively supported in XHTML Content Documents (in the case of MathML and SVG), but such support is not a requirement.
Element name
case
Namespace
Usage
Required first child of
switch
. Repeatable.
Attributes
id
[optional]
The ID
XML
of this element, which
must
be unique within the document scope.
required-namespace
[required]
An extension identifier in URI form
RFC2046
that identifies the XML vocabulary or extension that the Reading System
must
support in order to process the content of the
case
element.
Content Model
An XML fragment conforming to the markup vocabulary identified in the
required-namespace
attribute.
Each
case
element
must
contain an alternate representation of the same content. To ensure the best rendering of their content, Authors
should
order
case
elements by to their optimal rendering format.
If the
case
element contains markup that is valid in an XHTML Content Document (e.g., MathML), that content
must
be valid at the point where the
switch
element has been inserted (i.e., its addition
must not
result in an invalid document).
Foreign markup in a
case
element
must
be well formed, but does not have to be valid at its point of insertion. Authors
should
ensure that any foreign markup matches the context in which it is used (e.g., a block element should not be included in a
switch
element inserted in an inline context).
note
The IDPF maintains an informative registry of common extension identifiers for use in the
required-namespace
attribute at
2.1.3.3.2.3 The
epub:default
Element
The
default
element provides markup that is valid in any XHTML Content Document for when a Reading System cannot render any of the
case
elements.
Element name
default
Namespace
Usage
Required last child of
epub:switch
Attributes
id
[optional]
The ID
XML
of this element, which
must
be unique within the document scope.
Content Model
An
HTML5
-compliant markup fragment.
The
default
element acts as a fallback for the
switch
and
must
include a representation of the content that is valid in XHTML Content Documents.
The
default
element
must not
include content that would invalidate the document at the point where the
switch
has been inserted: XHTML Content Documents
must
be valid if all the
switch
elements are replaced by their child
default
elements.
2.1.3.3.3 Processing
EPUB Reading System
must
support the
switch
element.
This specification does not require a specific rendering approach for
switch
elements. A Reading System
may
choose to apply CSS styling to render each
switch
, for example, but
may
use any other approach as appropriate. All Reading Systems
must
present the content of only one
case
element or the
default
element per
switch
for rendering, however.
The
switch
element
must
be processed as though all of its children but one have the HTML5
hidden
attribute set (i.e., apply the same processing rules and requirements outlined for that attribute to the content not to be rendered).
note
As the content that may be rendered depends on the capabilities of the User's Reading System, linking can be guaranteed only to the
switch
element. Deep referencing into the
switch
element is not recommended.
note
The occurrence of
switch
elements in
XHTML Content Document
is indicated in the
Package Document
manifest
through the
switch
Publications301
property.
2.1.3.4 The
epub:trigger
Element
The
trigger
element enables the creation of markup-defined user interfaces for controlling multimedia objects, such as audio and video playback, in both scripted and non-scripted contexts.
Element name
trigger
Namespace
Usage
As a child of
head
and in
Flow content
. Repeatable.
Attributes
id
[optional]
The ID
XML
of this element, which
must
be unique within the document scope.
action
[required]
The action to perform for this event.
Allowed values:
show
hide
play
pause
resume
mute
unmute
ref
[required]
An IDREF
XML
that identifies the element that is the object of the action.
ev:defaultAction
[optional]
The applicable event for this trigger, as defined in
XML Events
ev:event
[required]
The applicable event for this trigger, as defined in
XML Events
ev:observer
[required]
The source object for this trigger, as defined in
XML Events
ev:phase
[optional]
The applicable event for this trigger, as defined in
XML Events
ev:propagate
[optional]
The applicable event for this trigger, as defined in
XML Events
Content Model
Empty.
The
trigger
element associates an
event
from a specified source object (
observer
) with a desired action to be performed with a specified target object (
ref
).
The semantics of the defined
action
values are:
show
– set the element's DOM
visibility
CSS2.1
property to visible.
hide
– set the element's DOM
visibility
CSS2.1
property to hidden.
play
– play the associated resource from the beginning.
pause
– pause playing.
resume
– resume playing.
mute
– mute sound.
unmute
– unmute sound.
Reading Systems that support the
HTML5
audio
or
video
elements
must
support the
epub:trigger
element. The
play
pause
resume
mute
and
unmute
actions can be applied to
audio
and
video
elements only. The
show
and
hide
actions can be applied to any descendant of the
body
element.
Sample markup of a video player that uses
trigger
elements to control playback and muting. The
role
tabindex
and
aria-controls
attributes ensure the
span
elements are accessible as buttons to keyboard users.
xmlns:epub="http://www.idpf.org/2007/ops"
xmlns:ev="http://www.w3.org/2001/xml-events">










Play/Resume
Pause
Mute
Unmute
MUTED




2.1.3.5 Alternate Style Tags
In accordance with
AltStyleTags
, the
link
element
class
attribute
may
include any of the following values:
horizontal
vertical
day
and
night
. These values inherit the semantics defined by that specification for their use.
Reading Systems
should
select and utilize such tagged style sets as appropriate, and as described in that specification.
2.1.3.6 Custom Attributes
EPUB Reading System
may
introduce functionality not defined in this specification to enhance the rendering of
EPUB Publication
s. To facilitate this experimentation, vendors
may
define custom attributes for use in
XHTML Content Document
s.
Custom attributes
may
be included on any element in an XHTML Content Document provided such attributes are from a foreign namespace, which is defined as a namespace
XMLNS
that does not map to either of the following URIs:
Custom attributes, and the behaviors associated with them,
must not
alter the integrity of an EPUB Publication. The content
must
remain consumable by a User without any information loss or other significant deterioration, regardless of the Reading System it is rendered on.
note
To facilitate interoperability of custom attributes across Reading Systems, vendors are strongly encouraged to document any extensions they implement at
2.1.3.7 The
aria-describedat
Attribute
caution
The
aria-describedat
attribute has been removed from ARIA 1.1. Use of the attribute in EPUB is now deprecated. Please see
the errata
for more information.
The
aria-describedat
attribute from
WAI-ARIA-1.1
may
be specified on all elements in
XHTML Content Document
s, using the syntax and semantics defined in that specification. This attribute
may
be used to reference descriptions outside the
EPUB Container
(see
Publication Resource Locations
Publications301
).
Reading System support for this attribute is
optional
note
EPUB 3 does not support the full ARIA 1.1 specification at this time.
2.1.4 HTML5 Deviations and Constraints
This section defines deviations from, and constraints on, the underlying
HTML5
document model applicable to EPUB 3
XHTML Content Document
s.
2.1.4.1 Embedded MathML
2.1.4.1.1 Introduction
This section is informative
XHTML Content Documents support embedded
MATHML
but limit its usage to a restricted subset of the full MathML markup language.
This subset is designed to ease the implementation burden on Reading Systems and to promote accessibility, while retaining compatibility with
HTML5
User Agents.
note
The
mathml
Publications301
property of the
manifest
item
element indicates that an XHTML Content Document contains embedded MathML.
2.1.4.1.2 Content Conformance
Any occurrence of MathML markup in XHTML Content Documents
must
conform to the constraints expressed in the MathML specification
MATHML
, with the following additional restrictions:
Presentation MathML
The
m:math
element
must
contain only
Presentation MathML
, with the exception of the
m:annotation-xml
element as defined below.
Content MathML
Content MathML
may
be included within MathML markup in XHTML Content Documents, and, when present,
must
occur within an
m:annotation-xml
child element of an
m:semantics
element.
When Content MathML is included as per the previous condition, the given
m:annotation-xml
element's
encoding
attribute
must
be set to either of the functionally-equivalent values
MathML-Content
or
application/mathml-content+xml
, and its
name
attribute
must
be set to
contentequiv
Deprecated MathML
Elements and attributes marked as deprecated in
MATHML
must not
be included within MathML markup in XHTML Content Documents.
XHTML Content Document fragments
XHTML Content Document fragments
may
be included within MathML markup in XHTML Content Documents, and, when present,
must
occur within an
m:annotation-xml
child element of an
m:semantics
element.
When an XHTML Content Document fragment is included as per the above paragraph, the given
m:annotation-xml
element's
encoding
attribute
must
be set to
application/xhtml+xml
and its
name
attribute
must
be set to
alternate-representation
Any included XHTML Content Document fragments
must not
themselves contain MathML markup.
Any included XHTML Content Document fragments
must
conform to the content model in which the ancestor
m:math
element occurs, such that if the
m:math
element is replaced by the given XHTML Content Document fragment the document remains valid.
Alternative Content
Alternative content
should
be included, and, when present,
must
be represented as defined in
Alternative Content
2.1.4.1.3 Reading System Conformance
A conformant
EPUB Reading System
must
meet all of the following criteria for processing MathML embedded in XHTML Content Documents:
It
must
support processing of
Presentation MathML
, and
may
support processing of
Content MathML
, using semantics defined by the MathML 3.0 specification
MATHML
If it has a
Viewport
, it
must
support visual rendering of Presentation MathML.
When producing
alternative textual content
for MathML markup, it
should
be able to dynamically generate such content from the given
Presentation MathML
, and if not,
must
give preference to
XHTML Content Document fragments
followed by the
alttext
attribute on the
m:math
element.
It
must
regard the
mathml
Publications301
property of the
Package Document
manifest
item
element as the authoritative definition of whether an XHTML Content Document includes embedded MathML.
2.1.4.1.4 Alternative Content
Reading Systems
should
be able to generate any necessary alternative textual rendering dynamically using the given
Presentation MathML
markup (e.g., as output to
Text-to-Speech (TTS)
engines). To support Reading Systems that are not so capable, alternative textual content
should
be included with each occurrence of the
m:math
element in XHTML Content Documents.
The
alttext
attribute on the
m:math
element
should
be used for this purpose primarily when shorter alternative text runs are sufficient. When more extensive alternative text is required,
XHTML Content Document fragments
should
be used. (Note that Reading Systems query these two alternative text locations using a defined
preference order
.)
For Reading System forward compatibility purposes, fallback images
may
be provided using the
altimg
attribute on the
m:math
element. It is
recommended
that the dimension and alignment attributes (
altimg-width
altimg-height
and
altimg-valign
) be used in conjunction with the
altimg
attribute.
note
All referenced
Publication Resource
s must conform to the constraints for Publication Resources defined in
EPUB Publication — Content Conformance
Publications301
2.1.4.2 Embedded SVG
XHTML Content Document
s support the embedding of
SVG 1.1 document fragments
by reference
(embedding via reference, for example, from an
img
or
object
element) and
by inclusion
(embedding via direct inclusion of the
svg:svg
element in the XHTML Content Document)
SVG
The content conformance constraints for SVG embedded in XHTML Content Documents are the same as defined for
SVG Content Document
s in
Restrictions on SVG 1.1
Reading Systems
must
process SVG embedded in XHTML Content Documents as defined in
SVG Content Documents — Reading System Conformance
note
The
svg
Publications301
property of the
manifest
item
element indicates that an XHTML Content Document contains embedded SVG.
2.1.4.2.1 Embedded SVG and CSS
For the purposes of styling SVG embedded in XHTML Content Documents
by reference
, Reading Systems
must not
apply CSS style rules of the containing document to the referenced SVG document.
For the purposes of styling SVG embedded in XHTML Content Documents
by inclusion
, Reading Systems
must
apply applicable CSS rules of the containing document to the included SVG elements.
note
SVG included
by reference
is processed as a separate document, and may include its own CSS style rules just like an
SVG Content Document
would. Note that this is consistent with situations where an
HTML5
object
element references an external
HTML5
element.
2.1.4.3 Unicode Restrictions
This section lists restrictions on the Unicode character repertoire.
Private Use Characters and Embedded Fonts
Any included characters that map to a code point within one of the Private Use Area (PUA) ranges as defined in
Unicode
must
occur within a string that is styled or attributed in a manner that includes a reference to an
embedded font
that contains an appropriate glyph for that code point.
2.1.4.4 Discouraged Constructs
The
rp
Element
The
HTML5
rp
element is intended to provide a fallback — an optional parenthesis display around
ruby
markup — for older version Reading Systems that do not recognize ruby markup. As EPUB 3 Reading Systems are ruby-aware, and can provide fallbacks, the use of
rp
elements in Content Documents is discouraged.
The
embed
Element
Since the
HTML5
embed
element does not provide intrinsic facilities to provide
fallbacks
for Reading Systems that do not support scripting, its use is discouraged when the resource referenced has scripting components. Authors
should
use the
object
element instead.
2.1.4.5 Special Considerations
2.1.4.5.1 The
body
element
It is assumed, in formatting, that the default rendering for the
HTML5
body
element is consistent with the
CSS2.1
page-break-before
property having been set to
always
, but this default
may
be overridden by an appropriate style sheet declaration.
2.2 EPUB Navigation Documents
2.2.1 Introduction
This section is informative
The EPUB Navigation Document is a
required component
Publications301
of
EPUB Publication
s. It provides the Author with a mechanism to include a human- and machine-readable global navigation layer in the EPUB Publication, thereby ensuring increased usability and accessibility for the User.
The EPUB Navigation Document is an adaptation of
XHTML Content Document
and is,
by definition
, a valid XHTML Content Document instance. All Content and Reading System conformance requirements that apply to XHTML Content Documents also apply to the EPUB Navigation Document.
The navigation features of this adaptation are expressed through specializations of the
HTML5
nav
element. Each
nav
element in an EPUB Navigation Document represents a data island — an embedded source of specialized information within the general markup — from which Reading Systems can retrieve navigational information. Unlike typical XML data islands, however, the information within the
nav
element remains human readable as an
HTML5
document.
To facilitate machine readability, the content model of
nav
elements in EPUB Navigation Documents is restricted relative to what is allowed in general XHTML Content Documents.
Note that the navigation document is not exclusively for machine processing. Formulating the document as an XHTML Content Document enables its reuse in the linear reading order of an EPUB Publication, avoiding the creation of additional tables of contents (i.e., it can also be added to the
spine
Publications301
). The visual display of components defined in the navigation document can be controlled using the
hidden
attribute, which has no effect outside of spine rendering (i.e., hiding a component from rendering in the spine does not hide it from Reading System presentation in a custom control).
When designing a navigation document for such dual use, however, be aware that machine extraction of the content can result in loss of formatting control. Scripting, styling and other HTML formatting can be stripped by a Reading System as it generates a custom control, such as the table of contents, from the markup. If such formatting and functionality is used, then the Navigation Document also needs to be included in the linear reading order. Another design consideration is to to use
progressive enhancement
techniques for scripting and styling of the navigation document, such that that the content will retain its integrity when rendered in a non-browser context.
note
The EPUB Navigation Document is identified in the
Package Document
manifest
through the
nav
Publications301
property.
note
The EPUB Navigation Document supersedes the NCX document type as defined in
OPF2
Information on how EPUB 3 Publications may include an NCX document for EPUB 2 Reading System forwards compatibility purposes is available in
NCX Superseded
Publications301
2.2.2 Content Conformance
A conformant
EPUB Navigation Document
must
meet all of the following criteria:
Document Properties
It
must
conform to all content conformance constraints for
XHTML Content Document
s as defined in
XHTML Content Documents — Content Conformance
It
must
conform to all content conformance constraints specific for EPUB Navigation Documents expressed in
EPUB Navigation Document Definition
As a conforming XHTML Content Document, it
may
be included in a
Rendition
's
spine
2.2.3 Reading System Conformance
A conformant
EPUB Reading System
must
meet all of the following criteria for processing
EPUB Navigation Document
s:
When requested by a User, Reading Systems
must
provide access to the links and link labels in
the
nav
elements
of the EPUB Navigation Document in a fashion that allows the User to activate the links provided. When a link is activated, the Reading System
must
relocate the application's current reading position to the destination identified by that link.
Reading Systems
must
honor the above requirement irrespective of whether the EPUB Navigation Document provided in a
Rendition
is part of the
spine
2.2.4 EPUB Navigation Document Definition
2.2.4.1 The
nav
Element: Restrictions
When a
nav
element carries the
epub:type
attribute in an
EPUB Navigation Document
, this specification restricts the content model of the element and its descendants as follows:
Each
nav
element
may
contain an optional heading indicating the title of the navigation list. The heading
must
be an
HTML5 heading content
element.
The optional heading
must
be followed by a single
ol
ordered list; no other elements are permitted as direct children of the
nav
element. This ordered list represents the primary level of content navigation.
Each list item (
li
) of the ordered list represents a primary heading, structure or other point of interest within the EPUB Publication and
must
contain either a child
element or a child
span
element. The
element describes the target within the Content Document that the link points to. The
span
element serves as a heading for breaking down lists into distinct groups (for example, a large list of illustrations can be segmented into several lists, one for each chapter).
Each child
or
span
element of a list item
may
contain any valid
HTML5 phrasing content
, but
must
provide a non zero-length text label after concatenation of all child content and application of whitespace normalization rules. Although non-textual descendant elements
may
be rendered directly to Users, text content included in
title
or
alt
attributes
must
be used when determining compliance with this requirement.
If an
or
span
element contains instances of
HTML5 embedded content
that do not provide intrinsic text alternatives, it
must
also include a
title
attribute with an alternate text rendering of the link label.
The relative IRI reference provided in the
href
attribute of the
element
must
resolve to an
EPUB Content Document
or fragment therein.
The
element
may
optionally be followed by an
ol
ordered list representing a subsidiary content level below that heading (e.g., all the subsection headings of a section). The
span
element
must
be followed by an
ol
ordered list: it cannot be used in "leaf"
li
elements. Regardless of whether an
or
span
element precedes it, this sublist
must
adhere to all the content requirements defined in this section for constructing the primary navigation list, and recursively (for each additional level of the EPUB Publication's hierarchy represented in this manner).
The
ol
element represents an ordered list. In the context of this specification, the default display style of list items
must
be equivalent to CSS
list-style: none
(Reading Systems with no CSS support
must not
show list item numbering). Authors
may
specify alternative list item styles using CSS, but these would obviously be ignored by Reading Systems that do not support Cascading Style Sheets.
IDPF specifications
may
introduce further restrictions on the content model defined above for
nav
elements in the EPUB Navigation Document.
The following example shows a partial
lot
("list of tables")
nav
element, with
span
elements used as link-less headings for grouping the sublists.

2.2.4.2 The
nav
Element: Types
The
nav
elements defined in an EPUB Navigation Document are distinguished semantically by the value of their
epub:type
attribute. By
default
, values of
epub:type
are drawn from the EPUB 3 Structural Semantics Vocabulary
StructureVocab
, but values drawn from other vocabularies are also allowed. Refer to
The
epub:type
Attribute
for more information.
2.2.4.2.1 The
toc
nav
Element
The
toc
nav
element defines the primary navigational hierarchy of the
EPUB Publication
. It conceptually corresponds to a table of contents in a printed work (i.e., it provides navigation to the structural sections of the EPUB Publication).
For usability and accessibility reasons,
Author
should
provide a comprehensive table of contents: the
toc
nav
should not
exclude references based solely on their nesting depth within the document hierarchy, as is often the case in print works (particularly in reduced tables of contents).
In the case of
Rendition
s that exclusively reference XHTML Content Documents from their spines, the
toc
nav
will typically correspond to the aggregation of
HTML5 outlines
of those documents (excluding any subtrees that do not contribute to the primary outline).
The order of
li
elements contained within the
toc
nav
element
must
match the order of the targeted elements within each
targeted EPUB Content Document
, and
must
also follow the order of Content Documents in the Rendition's
spine
The
toc
nav
element
must
occur exactly once in EPUB Navigation Documents.
note
The
toc
nav
element corresponds to the
navMap
element in the superseded NCX
OPF2
2.2.4.2.2 The
page-list
nav
Element
The
page-list
nav
element is a container for pagination information. It provides navigation to positions in the content that correspond to the locations of page boundaries present in a print source being represented by the EPUB Publication.
The
page-list
nav
element is
optional
in EPUB Navigation Documents and
must not
occur more than once.
The order of
li
elements contained within a
page-list
nav
structure
must
match the order of the actual pages inside each
targeted EPUB Content Document
and
must
also follow the order of Content Documents in the
Rendition
's
spine
The
page-list
nav
element
should
contain only a single
ol
descendant (i.e., it
should
be a flat list, not a nested structure of navigation items).
note
The
page-list
nav
element corresponds to the
pageList
element in the superseded NCX.
OPF2
note
The
dc:source
Publications301
element provides a means of identifying the source publication to which the given pagination information applies.
2.2.4.2.3 The
landmarks
nav
Element
The
landmarks
nav
element identifies fundamental structural components of the EPUB Publication in order to enable Reading Systems to provide the User efficient access to them.
The structural semantics of each link target within the
landmarks
nav
element is determined by the value of the
epub:type
attribute on the
element descendants. The
epub:type
attribute is
required
on
element descendants of the
landmarks
nav
element.
The
landmarks
nav
element extends the suggested HTML context of terms from the
EPUB Structural Semantics Vocabulary
to include the
element.
The following example shows a
landmarks
nav
element with structural semantics drawn from the
EPUB Structural Semantics Vocabulary

The
landmarks
nav
element is
optional
in EPUB Navigation Documents and
must not
occur more than once.
note
The
landmarks
nav
element corresponds to the deprecated OPF
guide
element. Refer to
guide
Publications301
for more information.
2.2.4.2.4 Other
nav
Elements
EPUB Navigation Documents optionally
may
include one or more
nav
elements in addition to the
toc
page-list
and
landmarks
nav
elements defined above. Such additional
nav
elements
should
have an
epub:type
attribute to provide a machine-readable semantic, and
must
have a human-readable heading as their first child.
This specification imposes no restrictions on the semantics of such additional
nav
elements: they
may
be used to represent navigational semantics for any information domain, and they
may
contain link targets with homogeneous or heterogeneous semantics.
2.2.4.3 The
hidden
attribute
In some cases,
Author
s may wish to hide parts of the navigation data within the content flow (i.e., the Reading System's principal rendering of the
spine
contents). A typical example is the
list of page breaks
, which usually isn't rendered as part of the content flow but instead exposed to the
User
separately in a dedicated navigation user interface.
While the CSS
display
property can be used to control the visual rendering of EPUB Navigation Documents in Reading Systems with
CSS Viewport
s, not all Reading Systems provide such an interface. To control rendering across all Reading Systems, authors
must
use the
HTML5
hidden
attribute to indicate which (if any) portions of the navigation data are excluded from rendering in the content flow. The
hidden
attribute has no effect on how navigation data is rendered outside of the content flow (such as in dedicated navigation user interfaces provided by Reading Systems).
The following example shows a partial
page-list
nav
element. The presence of the
hidden
attribute on the root indicates that the entire list is excluded from rendering in the content flow.

The following example shows a partial
toc
nav
element where the
hidden
attribute is used to limit content flow rendering to the two topmost hierarchical levels.

2.3 SVG Content Documents
2.3.1 Introduction
This section is informative
The Scalable Vector Graphics (SVG) 1.1 (Second Edition) specification
SVG
defines a format for representing final-form vector graphics and text.
Although an EPUB Publication typically uses
XHTML Content Documents
as the
top-level
document type, the use of
SVG Content Document
s is also permitted. SVGs are typically only used in certain special circumstances, such as when final-form page images are the only suitable representation of the content (as may be the case, for example, in the context of manga or comic books).
This section defines a profile for
SVG
documents. An instance of an XML document that conforms to this profile is a
Core Media Type
and is referred to in this specification and its
sibling specifications
as an
SVG Content Document
note
This section defines conformance requirements for
SVG Content Document
s. Refer to
Embedded SVG
for conformance requirements for SVG embedded in XHTML Content Documents.
2.3.2 Content Conformance
An
SVG Content Document
must
meet all of the following criteria:
Document Properties
It
must
meet the conformance constraints for XML documents defined in
XML Conformance
Publications301
It
must
be an
SVG 1.1 document fragment
valid to the constructs defined in that specification, and conform to all content conformance constraints expressed in
Restrictions on SVG 1.1
It
should
adhere to the accessibility guidelines given in
SVG Access
File Properties
The SVG Content Document filename
should
use the file extension
.svg
note
All
Publication Resource
s referenced from an SVG Content Document must conform to the constraints for Publication Resources defined in
EPUB Publication — Content Conformance
Publications301
2.3.3 Restrictions on SVG 1.1
This specification restricts the content model of
SVG Content Document
s and
SVG embedded in XHTML Content Documents
as follows:
The
SVG
Animation Elements
and
Animation event attributes
must not
occur.
The
SVG
svg:foreignObject
element
must
contain either
HTML5
flow content
or exactly one
HTML5
body
element
. This content
must
represent a valid document fragment of the XHTML Content Document model defined in
XHTML Content Documents — Content Conformance
. The
svg:foreignObject
element's
requiredExtensions
attribute, if given,
must
be set to
The
SVG
svg:title
element
must
contain only valid XHTML Content Document Phrasing content.
2.3.4 Reading System Conformance
A conformant
EPUB Reading System
must
meet all of the following criteria for processing SVG Content Documents and SVG
embedded in XHTML Content Documents
It
must
support the language features of SVG that correspond to the feature string
minus the
and
features (see
Feature strings
SVG
It
must
meet the Reading System conformance criteria defined in
Scripted Content Documents — Reading System Conformance
If it has an
SVG Viewport
, it
must
support the visual rendering of SVG using CSS as defined in
Section 6
of
SVG
, and it
should
support all properties defined in
Appendix N
of that specification. In the case of embedded SVG, it
must
also conform to the constraints defined in
Embedded SVG and CSS
It
should
support User selection and searching of text within SVG elements.
It
must
recognize the value
of the
requiredExtensions
attribute when appearing on the
svg:switch
and
svg:foreignObject
elements as representing the occurrence of XHTML Content Document fragments.
It
must
regard the
svg
Publications301
property of the
Package Document
manifest
item
element as the authoritative definition of whether an EPUB XHTML Content Document includes embedded SVG.
2.3.5 Semantic Inflection
The synatx and semantics defined in
XHTML Semantic Inflection
are inherited for use of the
epub:type
and
epub:prefix
attributes in
SVG Content Document
s.
The use of the
epub:prefix
attribute is valid on the root
svg
element in SVG Content Documents. Prefixes used in
embedded SVG
must be declared on the
HTML5
root
html
element, as defined in
XHTML Semantic Inflection
2.4 Scripted Content Documents
EPUB Content Document
may
contain scripting using the facilities defined for this in the respective underlying specifications (
HTML5
and
SVG
). When an EPUB Content Document contains scripting, it is referred to in this specification and its
sibling specifications
as a
Scripted Content Document
. This label also applies to
XHTML Content Document
s when they contain instances of
HTML5 forms
2.4.1 Scripting Contexts
This specification defines two contexts in which scripts
may
appear:
spine-level
An instance of the
HTML5
script
element included in a
Top-level Content Document
container-constrained
An instance of the
HTML5
script
element included in an
EPUB Content Document
that is embedded in a parent Content Document using one of the
HTML5
object
iframe
or
embed
elements.
In both of the above-defined contexts, whether the JavaScript code is embedded directly in the
script
element or referenced via its
src
attribute makes no difference to the executing context.
Which context a script is used in determines the rights and restrictions that a Reading System may place on it. Refer to
Content Conformance
and
Reading System Conformance
for some specific requirements that must be adhered to (not all Reading Systems may provide the same scripting functionality).
Example
Consider the following example Package Document:


href="scripted01.xhtml"
media-type="application/xhtml+xml"
properties="scripted"/>
href="scripted02.xhtml"
media-type="application/xhtml+xml"
properties="scripted"/>
href="slideshow.js"
media-type="text/javascript"/>





and the following file
scripted01.xhtml