Publication Resources are listed in the Package Document manifest and bundled in the EPUB Container file unless specified otherwise - in .
+Publication Resources are typically listed in the Package Document manifest and bundled in the EPUB Container, with + two exceptions:
+resources encoded as data URLs are not required to be + listed in the manifest; and
+resources listed in may be located outside the + EPUB Container.
+Examples of resources that are not Publication Resources include those identified by the
Package Document link element and those identified
in outbound hyperlinks that resolve to Remote Resources (e.g., referenced from the
@@ -1001,6 +1011,55 @@
The data: URL scheme [[!RFC2397]]
+ is used to encode resources directly into a URL string. The advantage of this scheme is that it
+ allows a resource to be embedded within another, avoiding the need for an external file.
EPUB Creators MAY use data URLs in EPUB Publications provided their use does not result in + a Top-level Content Document or top-level browsing context [[!HTML]]. This restriction applies to data URLs used in the + following scenarios:
+ +in manifest item elements referenced from the
+ spine;
in the href attribute on [[!HTML]] or [[!SVG]] a elements
+ (except when inside an iframe element [[!HTML]]);
in the href attribute on [[!HTML]] area elements (except when
+ inside an iframe element);
in calls to [[!ECMASCRIPT]] window.open or document.open.
The list of prohibited uses for data URLs is subject to change as the respective standards + that allow their use evolve.
+This restriction on their use is to prevent security issues and also to ensure that Reading + Systems can determine where to take a user next (i.e., because these resources are not + be listed in the spine).
+ +Resources represented as data URLs are not Publication Resources so are exempt from the + requirement to be listed in the manifest.
+ +Data URLs MUST encode Core Media Types or be used where a fallback to one is provided (i.e., they + are subject to the foreign resource restrictions).
+title ElementFor example, the following example shows a basic multipart title:
- +<metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
<dc:title>THE LORD OF THE RINGS</dc:title>
<dc:title>Part One: The Fellowship of the Ring</dc:title>
@@ -1803,7 +1862,7 @@ The title Element
The same title could instead be expressed using a single dc:title
element as follows:
<metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
<dc:title>
THE LORD OF THE RINGS, Part One: The Fellowship of the Ring
@@ -2820,7 +2879,6 @@ Examples
Spine:
<itemref idref="audio01" linear="no"/>
-
Fallbacks MAY also be provided for Top-Level Content Documents that are EPUB Content Documents. An example of when this feature can be utilized is when providing fallbacks for scripted content.
+ +As it is not possible to use manifest fallbacks for resources represented in data URLs, Foreign Resources can only be represented + as data URLs where an intrinsic fallback mechanism is available.
+container.xml, encryption.xml and
signatures.xml files. All schemas are considered informative. See EPUB Publications
href="https://www.w3.org/TR/epub-33/#sec-resource-locations">Resource Locations
[[!EPUB-33]].
It MUST prevent data URLs [[!RFC2397]] from opening in top-level browsing contexts [[HTML]], except when initiated through a Reading + System affordance such as a context menu. If a Reading System does not use a top-level + browsing context for Top-level Content Documents, it MUST also prevent data URLs + from opening as though they are Top-level Content Documents.
+It MUST process XHTML Content Document as defined in .
@@ -2159,6 +2167,8 @@