Test Case sc1.1.1_l1_027: Long description for complex image: longdesc refers to separate HTML page

Formal Metadata

Formal Metadata
TitleLong description for complex image: longdesc refers to separate HTML page
DescriptionA document with an image that represents a map of the Mediterranean in 180 AD. The img element has an alt attribute, a title attribute and a longdesc attribute. The alt attribute identifies the image but the image is too complex to be described in an attribute. The longdesc attribute refers to a separate HTML page that identifies the image and conveys the same information.
CreatorBenToWeb (Christophe.Strobbe@…)
RightsCopyright BenToWeb 2005-2007
LanguageEnglish
Date2005-08-29
Statusvalidated

Technologies and Features

Technologies are markup languages or data formats. If the technology is a markup language, “features” refers to elements and attributes.

XHTML™ 1.0 The Extensible HyperText Markup Language (Second Edition)

XHTML™ 1.0 The Extensible HyperText Markup Language (Second Edition)

Feature: img (namespace: http://www.w3.org/1999/xhtml) .

Technical specification: How to specify alternate text .

Feature: img (namespace: http://www.w3.org/1999/xhtml) .

Technical specification: The longdesc attribute .

Test Data

Purpose

This test case is intended to fail because the alt attribute provides a short description but the longdesc attribute, which points to a separate page that contains an appropriate text alternative, cannot be accessed by some recent user agents. (The test is for the longdesc attribute rather than the alt attribute. Strictly speaking, this should work, but poor support for longdesc in some browsers may cause problems.)

Test Modes

Accessibility expert.

Test Files

Test file.

TCDL Data

sc1.1.1_l1_027 (XML).

Rules

“Rules” refer to success criteria in WCAG 2.0, checkpoints in WCAG 1.0 and similar requirements.

Primary Rules

The test case fails the following success criterion at line 10, column 59: http://www.w3.org/TR/2007/WD-WCAG20-20070517/Overview.html#text-equiv-all.

The test case fails the following success criterion at line 10, column 222: http://www.w3.org/TR/2007/WD-WCAG20-20070517/Overview.html#text-equiv-all.

Functional Outcome

The image has a short text description as well as a long one. User testing provided the following results: users of screenreaders with Internet Explorer 6 had no problems accessing the long description of the map, but users of screenreaders with Firefox had problems.

Technical Comment

The img element has an alt attribute and a longdesc attribute. However, due to lack of support of the longdesc attribute in some browsers, user may not always be able to access the long description.

Secondary Rules

Secondary Rule (WCAG 2.0 - April 2006 Working Draft (Last Call))

The test case fails the following success criterion at line 10, column 59: http://www.w3.org/TR/2006/WD-WCAG20-20060427/guidelines.html#text-equiv-all.

The test case fails the following success criterion at line 10, column 222: http://www.w3.org/TR/2006/WD-WCAG20-20060427/guidelines.html#text-equiv-all.

Functional Outcome

The image has a short text description as well as a long one. User testing provided the following results: users of screenreaders with Internet Explorer 6 had no problems accessing the long description of the map, but users of screenreaders with Firefox had problems.

Technical Comment

The img element has an alt attribute and a longdesc attribute. However, due to lack of support of the longdesc attribute in some browsers, user may not always be able to access the long description.

Secondary Rule (WCAG 2.0 - June 2005 Working Draft)

The test case passes (line 10, column 59) the following success criterion: http://www.w3.org/TR/2006/WD-WCAG20-20050630/#text-equiv-informative.

The test case passes (line 10, column 222) the following success criterion: http://www.w3.org/TR/2006/WD-WCAG20-20050630/#text-equiv-informative.

Functional Outcome

The image has a short text description as well as a long one.

Technical Comment

The img element has an alt attribute and a longdesc attribute. However, due to lack of support of the longdesc attribute in some browsers, user may not always be able to access the long description.

Secondary Rule (WCAG 2.0 - February 2005 Editor's Draft)

The test case passes the following success criterion: http://www.w3.org/WAI/GL/WCAG20/WD-WCAG20-20050211/#4.1_use-spec-document-backward-compat-violations.

Functional Outcome

The image has a text description.

Technical Comment

The img element has an alt attribute with appropriate alternative text and therefore the img element is valid.