Attribute Types (XHTML 1.1)

 

This page details the Attribute Types which are applicable to the standard *XHTML 1.1 DTD covered on this site. Those Attribute Types which apply only to Modules which are not included in the DTD (e.g. Legacy Module, Frames Module) are not listed below.

Attribute Types Defined by XML 1.0

The following types are defined in the XML 1.0 Recommendation. (Ref: *XML 1.0 Attribute Types)

CDATA
Arbitrary character data
Enumeration
If present, the attribute must take one of the listed values
ID
An element identifier which must be unique to the document. It may consist of any combination of letters, digits, and the four punctuation characters _:.- but must begin with a letter, a colon or an underscore
IDREF
A reference to an element identifier of type ID
IDREFS
A space-separated list of one or more IDREF values
NMTOKEN
A name which may consist of any combination of letters, digits, and the four punctuation characters _:.-
NMTOKENS
A space-separated list of one or more NMTOKEN values

Attribute Types Defined by XHTML 1.1

These attribute types are specific to XHTML Modularisation 1.1 but each must be declared in the DTD as one of the native Attribute Types Defined by XML 1.0.
According to the DTD, all the following types are declared as CDATA, apart from Boolean and Shape (which are declared as Enumeration) and LinkTypes (which is declared as NMTOKENS). [For more information see *W3C - XHTML Modularisation 1.1 - Attribute Types, but note that the Boolean type is not explicitly mentioned there - it is merely a helpful term, in common use, which is applied to such enumerated types.]

Boolean
A Boolean attribute. This is a type assigned to certain optional "on/off" attributes - if present, the attribute should be given its own name as its value, e.g. checked="checked"
Character
A single ISO 10646 Character, e.g. "x"
Charset
An RFC2045 Character Encoding, e.g. "utf-8", "US-ASCII" or "ISO-8859-1"
Charsets
A space-separated list of RFC2045 Character Encodings, e.g. "utf-8 US-ASCII ISO-8859-1"
ContentType
An RFC2045 MIME Media Type, e.g. "application/xhtml+xml", "application/xml", "text/xml", "text/html", "text/plain", "text/css", "text/javascript", "application/javascript", "application/octet-stream", "image/jpeg", "audio/mpeg", "multipart/form-data"
ContentTypes
A comma-separated list of RFC2045 MIME Media Types
Coords
Numerical coordinates specifying the dimensions and position of a shape (all x and y coordinates are measured from the top left corner of the image)
Datetime
Date and Time in the W3C profile of the ISO 8601 date format (YYYY-MM-DDThh:mm:ssTZD), e.g. "2006-01-31T13:52:10-05:00", "2006-05-28T21:01:26Z"
FPI
An SGML Formal Public Identifier
FrameTarget
A value indicating the window or frame in which to load a hyperlink (e.g. "_blank", "_top")
LanguageCode
An RFC3066 language code, e.g. "en" (Generic English), "en-GB" (British English), "en-US" (US English), "fr" (French), "he" (Hebrew)
Length
Length specified as a percentage or in pixels, e.g. "20%" or "10"
LinkTypes
A space-separated list of one or more link types
MediaDesc
A comma-separated list of one or more recognised media descriptors, e.g. "all", "screen", "screen, print"
MultiLength
This is a length specified in pixels (e.g. "400"), as a percentage of the available horizontal space (e.g. "20%") or as a relative unit "d*" where d is an integer (e.g. "1*", "3*")
Number
One or more digits, making up a single positive number (or zero) e.g. "34", "2"
Pixels
An integer specifying length in pixels, e.g. "3"
Script
A script expression to be passed to the appropriate scripting engine
Shape
A shape within an image, which can be "rect", "circle", "poly" or "default" (where "rect" denotes a rectangle and "poly" denotes a polygon)
Text
Arbitrary user-visible text
URI
A Uniform Resource Identifier
URIs
A space-separated list of Uniform Resource Identifiers

Important Notes for XHTML 1.1 Attributes

  • No single element may be given two attributes with the same name. (ref: well-formedness constraint of *XML 1.0 Start-Tags, End-Tags, and Empty-Element Tags)
  • Attributes may be specified in any order in the start-tag of an element
  • Each attribute must have been declared, with a specific Attribute Type, in the DTD for the element in question and must obey the rules for that Type.
  • Attribute names are case-sensitive (they are exclusively lower-case in XHTML 1.1).
  • All #REQUIRED attributes must be present. All #FIXED attributes, if present, must be given the declared default value. (see *XML 1.0 Attribute Defaults)
  • Attribute values may be delimited by either a pair of double quote (") characters or a pair of single quote (') characters. Both are equally valid for XML 1.0 documents (see *XML 1.0 AttValue definition) but double quote delimiters do tend to be more common (and are used throughout this reference).
  • Within attribute values:
    • Every less-than character (<) within an attribute value must be escaped as &lt; (or &#60;).
    • Every ampersand character (&) which does not denote the start of an entity or character reference (e.g. &lt;) must be escaped as &amp; (or &#38;).
    • Every double quote character (") must be escaped as &quot; (or &#34;) if using double quotes to delimit the attribute value
    • Every single quote character (') must be escaped as &#39; (or &#apos; - but see Character Entities Predefined by XML 1.0) if using single quotes to delimit the attribute value
  • For information on white-space handling in attributes, see *XML 1.0 Attribute-Value Normalisation.
  • If compatibility is between XML-based and HTML-based user agents, attribute values should not contain line breaks or multiple consecutive whitespace. Ref: the W3C Note (work in progress) *XHTML Media Types - Compatibility Guidelines - Item A.5

Page Footer & Copyright

Copyright © Sally Maughan 2005-2009 (Page last updated on 16 May 2009)

*Valid XHTML 1.1 - hosted by *Openstrike

Content based on the W3C Working Draft: *XHTML 1.1 and Recommendation: *XHTML Modularisation 1.1.

W3C, XHTML, XML, HTML, CSS and MathML are *Trademarks of the W3C (*MIT, *ERCIM, *Keio) with which the site's author has no connection.

Up, Next & Previous Links

Your Location

Home > XHTML 1.1 Home > Data Types in XHTML 1.1 > Attribute Types (XHTML 1.1)