Rule 1.4.2

Summary

This test consists in detecting captcha area and thus defining the applicability of the test.

Human check will be then needed to determine whether the alternative is pertinent.

Business description

Criterion

1.4

Test

1.4.2

Description

Chaque zone (balise area) d'une image réactive, utilisée comme CAPTCHA ou comme image-test, et ayant un attribut alt vérifie-t-elle ces conditions ?

  • le contenu de l'attribut alt permet d'identifier la nature et la fonction de la zone
  • s'il est présent, le contenu de l'attribut title est identique au contenu de l'attribut alt

Level

A

Technical description

Scope

Page

Decision level

Semi-Decidable

Algorithm

Selection

Set1

All the <area> tags, defined within a <map> tag whose the "id" attribute corresponds to the "usemap" attribute of an <img> tag, with a "href" and an "alt" attribute

Set2

All the elements of Set1 identified as a CAPTCHA (see Notes for details about CAPTCHA characterisation).

Process

Test1

For each element of Set2, raise a MessageA

MessageA : Check captcha alternative
  • code : CheckCaptchaAlternative
  • status: Pre-Qualified
  • parameter : "alt" attribute, "href" attribute, tag name, snippet
  • present in source : yes

Analysis

Not Applicable

The page has no <area> tag with a "href" and an "alt" attribute identified as a captcha (Set2 is empty)

Pre-qualified

In all other cases

Notes

Captcha detection

An element is identified as a CAPTCHA when the "captcha" occurrence is found :

  • on one attribute of the element
  • or within the text of the element
  • or on one attribute of one parent of the element
  • or within the text of one parent of the element
  • or on one attribute of a sibling of the element
  • or within the text of a sibling of the element