5. XHTML Abstract Modules

This section is normative.

This section specifies the contents of the XHTML abstract modules. These modules are abstract definitions of collections of elements, attributes, and their content models. These abstract modules can be mapped onto any appropriate specification mechanism. XHTML DTD Module Implementations, for example, maps these modules onto DTDs as described in [XML].

Content developers and device designers should view this section as a guide to the definition of the functionality provided by the various XHTML-defined modules. When developing documents or defining a profile for a class of documents, content developers can determine which of these modules are essential for conveying their message. When designing clients, device designers should develop their device profiles by choosing from among the abstract modules defined here.

Except when overridden in this document, the semantics of these elements and attributes are defined in [HTML4].

5.1. Attribute Collections

Many of the abstract modules in this section define the required attributes for elements. The table below defines some collections of attributes that are referenced throughout the modules. These expressions should in no way be considered normative or mandatory. They are an editorial convenience for this document. When used in the remainder of this section, it is the expansion of the term that is normative, not the term itself.

The following basic attribute sets are used on many elements. In each case where they are used, their use is identified via their collection name rather than enumerating the list.

Each of the attributes defined in an XHTML attribute collection is available for use when their corresponding module is included in an XHTML Host Language or an XHTML Integration Set. In such a situation, the attributes are available for use in the definition of elements that are NOT in the XHTML namespace when they are referenced using their namespace-qualified identifier (e.g., xhtml:class). The semantics of the attributes remain the same regardless of whether they are referenced using their qualified identifier or not. It is an error to use an XHTML namespace-qualified attribute on elements from the XHTML Namespace.

For the avoidance of doubt, if an attribute collection is referenced by an element's definition, and an attribute in that collection is also explicitly referenced by that element's definition, this does NOT cause a conflict. It is up to the markup language schema implementation to update the content models accordingly.

Note that the Events collection is only defined when the Intrinsic Events Module is selected. Otherwise, the Events collection is empty.

Also note that the Style collection is only defined when the Style Attribute Module is selected. Otherwise, the Style collection is empty.

Finally, note that the I18N collection only contains the xml:lang attribute unless the Bi-directional Text Module module is selected.

5.2. Core Modules

The core modules are modules that are required to be present in any XHTML Family Conforming Document Type.

5.2.1. Structure Module

The Structure Module defines the major structural elements for XHTML. These elements effectively act as the basis for the content model of many XHTML family document types. The elements and attributes included in this module are:

This module is the basic structural definition for XHTML content. The html element acts as the root element for all XHTML Family Document Types.

Note that the value of the xmlns attribute is defined to be "http://www.w3.org/1999/xhtml". Also note that because the xmlns attribute is treated specially by XML namespace-aware parsers [XMLNAMES], it is legal to have it present as an attribute of each element. However, any time the xmlns attribute is used in the context of an XHTML module, whether with a prefix or not, the value of the attribute shall be the XHTML namespace defined here. See Defining the Namespace of a Module for more on rules regarding namespace usage with XHTML family modules.

Implementations: DTD, XML Schema

5.2.2. Text Module

This module defines all of the basic text container elements, attributes, and their content model:

The minimal content model for this module defines some content sets:

Heading

h1 | h2 | h3 | h4 | h5 | h6

Block

address | blockquote | div | p | pre

Inline

abbr | acronym | br | cite | code | dfn | em | kbd | q | samp | span | strong | var

Flow

Heading | Block | Inline

Implementations: DTD, XML Schema

5.2.3. Hypertext Module

The Hypertext Module provides the element that is used to define hypertext links to other resources. This module supports the following element and attributes:

This module adds the a element to the Inline content set of the Text Module.

Implementations: DTD, XML Schema

5.2.4. List Module

As its name suggests, the List Module provides list-oriented elements. Specifically, the List Module supports the following elements and attributes:

This module also defines the content set List with the minimal content model (dl | ol | ul)+ and adds this set to the Flow content set of the Text Module.

Implementations: DTD, XML Schema

5.3. Applet Module

This module is deprecated. Similar functionality can be found in the Object Module.

The Applet Module provides elements for referencing external applications. Specifically, the Applet Module supports the following elements and attributes:

When the Applet Module is used, it adds the applet element to the Inline content set of the Text Module.

Implementations: DTD, XML Schema

5.4. Text Extension Modules

This section defines a variety of additional textual markup modules.

5.4.1. Presentation Module

This module defines elements, attributes, and a minimal content model for simple presentation-related markup:

When this module is used, the hr element is added to the Block content set of the Text Module. In addition, the b, big, i, small, sub, sup, and tt elements are added to the Inline content set of the Text Module.

Implementations: DTD, XML Schema

5.4.2. Edit Module

This module defines elements and attributes for use in editing-related markup:

When this module is used, the del and ins elements are added to the Inline content set of the Text Module.

Implementations: DTD, XML Schema

5.4.3. Bi-directional Text Module

The Bi-directional Text module defines an element that can be used to declare the bi-directional rules for the element's content.

When this module is used, the bdo element is added to the Inline content set of the Text Module. Selecting this module also adds the attribute dir ("ltr" | "rtl") to the I18N attribute collection.

Implementations: DTD, XML Schema

5.5. Forms Modules

5.5.1. Basic Forms Module

The Basic Forms Module provides the form-related elements, but only in a limited form. Specifically, the Basic Forms Module supports the following elements, attributes, and minimal content model:

This module defines two content sets:

Form

form

Formctrl

input | label | select | textarea

When this module is used, it adds the Form content set to the Block content set and it adds the Formctrl content set to the Inline content set as these are defined in the Text Module.

The Basic Forms Module is a subset of the Forms Module. These modules may not be used together in a single document type.

Implementations: DTD, XML Schema

5.5.2. Forms Module

The Forms Module provides all of the forms features found in HTML 4.0. Specifically, the Forms Module supports:

This module defines two content sets:

Form

form | fieldset

Formctrl

input | select | textarea | label | button

When this module is used, it adds the Form content set to the Block content set and it adds the Formctrl content set to the Inline content set as these are defined in the Text Module.

The Forms Module is a superset of the Basic Forms Module. These modules may not be used together in a single document type.

Implementations: DTD, XML Schema

5.6. Table Modules

5.6.1. Basic Tables Module

The Basic Tables Module provides table-related elements, but only in a limited form. Specifically, the Basic Tables Module supports:

When this module is used, it adds the table element to the Block content set as defined in the Text Module.

The Basic Tables Module is a subset of the Tables Module. These modules may not be used together in a single document type.

Implementations: DTD, XML Schema

5.6.2. Tables Module

As its name suggests, the Tables Module provides table-related elements that are better able to be accessed by non-visual user agents. Specifically, the Tables Module supports the following elements, attributes, and content model:

When this module is used, it adds the table element to the Block content set of the Text Module.

The Tables Module is a superset of the Basic Tables Module. These modules may not be used together in a single document type.

Implementations: DTD, XML Schema

5.7. Image Module

The Image Module provides basic image embedding, and may be used in some implementations independently of client side image maps. The Image Module supports the following element and attributes:

When this module is used, it adds the img element to the Inline content set of the Text Module.

Implementations: DTD, XML Schema

5.8. Client-side Image Map Module

The Client-side Image Map Module provides elements for client side image maps. It requires that the Image Module (or another module that supports the img element) be included. The Client-side Image Map Module supports the following elements:

When this module is used, the map element is added to the Inline content set of the Text Module.

Implementations: DTD, XML Schema

5.9. Server-side Image Map Module

The Server-side Image Map Module provides support for image-selection and transmission of selection coordinates. It requires that the Image Module (or another module that supports the img element) be included. The Server-side Image Map Module supports the following attributes:

Implementations: DTD, XML Schema

5.10. Object Module

The Object Module provides elements for general-purpose object inclusion. Specifically, the Object Module supports:

When this module is used, it adds the object element to the Inline content set of the Text Module.

Implementations: DTD, XML Schema

5.11. Frames Module

As its name suggests, the Frames Module provides frame-related elements. Specifically, the Frames Module supports:

When this module is selected, the minimal content model of the html element of the Structure Module is changed to (head, frameset).

Implementations: DTD, XML Schema

5.12. Target Module

The content of a frame can specify destination targets for a selection. This module adds the target attribute to the area and link defining elements. This is defined as a separate module so it can be included in documents that will be included in frames and documents that use the target feature to open a new window.

Implementations: DTD, XML Schema

5.13. Iframe Module

The Iframe Module defines an element for the definition of inline frames. The element and attribute included in this module are:

When this module is used, the iframe element is added to the Inline content set as defined by the Text Module.

Implementations: DTD, XML Schema

5.14. Intrinsic Events Module

Intrinsic events are attributes that are used in conjunction with elements that can have specific events occur when certain actions are performed by the user. The attributes indicated in the following table are added to the attribute set for their respective elements only when the modules defining those elements are selected. Note also that selection of this module defines the attribute collection Events as described above. Attributes defined by this module are:

When this module is selected, it activates the Events Attribute Collection.

Implementations: DTD, XML Schema

5.15. Metainformation Module

The Metainformation Module defines an element that describes information within the declarative portion of a document (in XHTML within the head element). This module includes the following element:

When this module is selected, the meta element is added to the content model of the head element as defined in the Structure Module.

Implementations: DTD, XML Schema

5.16. Scripting Module

The Scripting Module defines elements that are used to contain information pertaining to executable scripts or the lack of support for executable scripts. Elements and attributes included in this module are:

When this module is used, the script and noscript elements are added to the Block and Inline content sets of the Text Module. In addition, the script element is added to the content model of the head element defined in the Structure Module.

Implementations: DTD, XML Schema

5.17. Style Sheet Module

The Style Sheet Module defines an element to be used when declaring internal style sheets. The element and attributes defined by this module are:

When this module is used, it adds the style element to the content model of the head element of the Structure Module.

Implementations: DTD, XML Schema

5.18. Style Attribute Module

The Style Attribute Module defines the style attribute. When this module is selected, it activates the Style Attribute Collection.

Implementations: DTD, XML Schema

5.19. Link Module

The Link Module defines an element that can be used to define links to external resources. These resources are often used to augment the user agent's ability to process the associated XHTML document. The element and attributes included in this module are:

When this module is used, it adds the link element to the content model of the head element as defined in the Structure Module.

Implementations: DTD, XML Schema

5.20. Base Module

The Base Module defines an element that can be used to define a base URI against which relative URIs in the document will be resolved. The element and attribute included in this module are:

When this module is used, it adds the base element to the content model of the head element of the Structure Module.

Implementations: DTD, XML Schema

5.21. Name Identification Module

This module is deprecated.

The Name Identification Module defines the attribute name for a collection of elements. The name attribute was used historically to identify certain elements within HTML documents. While the name attribute has been supplanted by the id attribute in all of these elements, there may be instances where markup languages will wish to support both. Such markup languages may do so by including this module.

Note that by including this module, both the name and id attributes are defined for the elements indicated. In this situation, if the name attribute is defined for an element, the id attribute must also be defined. Further, these attributes must both have the same value. Finally, when documents that use this attribute are served as Internet Media Type "text/xml" or "application/xml", the value of the name attribute on these elements shall not be used as a fragment identifier.

Implementations: DTD, XML Schema

5.22. Legacy Module

This module is deprecated.

The Legacy Module defines elements and attributes that were already deprecated in previous versions of HTML and XHTML, and remain deprecated in XHTML Modularization. Markup language authors should no longer use these elements and attributes.

Note: This module is not intended to reproduce all of the deprecated elements, attributes, and content models. Just those that were thought to be of maximal use at the time this specification was written.

The following table defines the elements and attributes that are defined when the Legacy Module is selected.

The following table shows additional attributes for elements defined elsewhere when the Legacy module is selected.

Implementations: DTD, XML Schema