Asqatasun v4 - AccessiWeb 2.2 - Rule 1.2.1
Summary
This test consists in checking whether the alt
attribute of each decorative image is empty.
Business description
Criterion : 1.2
Test : 1.2.1
Test description :
For each decorative image (img tag) with an alt
attribute, is the content of this attribute empty (alt="")?
Level : Bronze
Technical description
Scope : page
Decision level : decidable
Algorithm
Selection
For this rule, we assume that all img
tags with a longdesc
attribute are informative images and the img
tags without src
attribute are ignored (unusable tag).
Set1 : All the img
tags of the page with an alt
attribute and a src
attribute but not within a <a>
tag (in this case, the image would be considered as a link)
Set2 : All the img
tags of the page with an alt
attribute, a src
attribute and a longdesc
attribute but not within a <a>
tag (in this case, the image would be considered as a link)
Set3 : All the img
tags of the page with an alt
attribute and a src
attribute but without a longdesc
attribute and not within a <a>
tag (in this case, the image would be considered as a link)
- used nomenclature : none
- reference : none
Process
For this rule, we assume that all img
tags with a longdesc
attribute are informative images.
Test1 : Test if Set1 and Set2 have the same size OR set1 is empty
Test2 : Returns elements of Set3 that are potentially decorative. We test if one dimension of each image is equal to 1 pixel or if it displays only one color.
Test3 : Test if elements returned by Test2 have an empty alt
attribute and a not empty src
attribute
- used nomenclature : none
- reference : none
Analysis
Not Applicable
- The page has no
img
tag withalt
attribute (Set2 is empty and Test1 returns true) - All the images of the page are informative (Set1 and Set2 have the same size and Test1 returns true)
Pre-qualified
All other cases with message:
- code : SuspectedDecorativeImageWithNotEmptyAltAttribute
- status: NMI
- case : For each element returning false in Test3
- parameter : tag name
- present in source : yes
Notes
No notes yet for that rule