Test Case sc1.1.1_l1_029: Long description for complex image: image inside object; longdesc on image refers to section inside object

Formal Metadata

Formal Metadata
TitleLong description for complex image: image inside object; longdesc on image refers to section inside object
DescriptionA document with an image that represents a map of the Mediterranean in 180 AD. The document contains an object element that embeds the map in GIF format; inside the object element is an img element that embeds the same map in JPEG format. 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 section inside the object element that identifies the image and conveys the same information.
CreatorBenToWeb (Christophe.Strobbe@…)
RightsCopyright BenToWeb 2005-2007
LanguageEnglish
Date2005-08-30
Statusaccepted QA

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

Technical specification: General Inclusion: The object element .

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 points to a section (with an appropriate text alternative) inside the object element that loads the map. The test is for the longdesc attribute rather than the alt attribute. (Strictly speaking, this should work, but poor support for longdesc and the object element in some browsers may cause problems, especially because the long description is inside the object element.)

Test Modes

Accessibility expert.

Test Files

Test file.

TCDL Data

sc1.1.1_l1_029 (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 12, column 60: http://www.w3.org/TR/2006/WD-WCAG20-20060427/guidelines.html#text-equiv-all.

The test case fails the following success criterion at line 12, column 223: 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 or Firefox had problems accessing the long description of the map.

Technical Comment

The img element has an alt attribute and a longdesc attribute.

This test is identical to sc1.1.1_l1_028 but the long description is moved into the object element. Since browsers do not necessarily provide access to the content of the object if the object can be displayed, it is not certain that the long description is available to users.

(Internet Explorer does not support object and is supposed to display the fallback image, but refuses.)

Secondary Rules

Secondary Rule (WCAG 2.0 - June 2005 Working Draft)

The test case needs review before it can be established if it passes or fails the following success criterion: http://www.w3.org/TR/2006/WD-WCAG20-20050630/#text-equiv-informative. The code that causes doubt can be found at line 12, column 60.

The test case needs review before it can be established if it passes or fails the following success criterion: http://www.w3.org/TR/2006/WD-WCAG20-20050630/#text-equiv-informative. The code that causes doubt can be found at line 12, column 223.

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.

This test is identical to xhtml1_wcag2_20050630_1.1_l1_sc1_028 but the long description is moved into the object element. Since browsers do not necessarily provide access to the content of the object if the object can be displayed, it is not certain that the long description is available to users.

(Internet Explorer does not support object and is supposed to display the fallback image, but refuses.)

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.