Non-text Content

Understanding WCAG2.0

There is an exception to omit alt in HTML5, but in order to apply this exception, please apply it after understanding the specification of HTML5 well. Even if this exception is applicable, this check tool issues a warning.

If it is an imaged character, in principle, alt matching the image is given. In addition, please, if possible, please carefully examine whether you really want to image that character.

Because the image of decorative purposes, have an alt in the sky. Even in this case, make sure to set alt="" and do not omit the alt attribute value. Incidentally, if you indicate that it is for decoration purposes with attribute values, such as role="presentation", you will not get a warning when checking this accessibility checker. It is not a recommendation to abuse role="presentation".

Users in low-speed line environments may have turned off image display. The appropriate alt is also a judgment of "whether to display the image dared", please put it as carefully as possible.

Since it is an image for skipping requests to images of other servers and analyzing logs, empty alt is inserted.

There is an image, but there is a character string duplicated with the image in the vicinity, and alt is omitted. (If there is an image of Mr. A and there is written "Mr. A" in the vicinity thereof, "Mr. A" Alternatively, alt such as "Mr. A's image" may be easier to read for screen readers if omitting alt).

In order to make it easy to distinguish between "imaged character" and "image", it is good to attach a prefix such as "photo: XX" or a descriptive alt like "XX photo". For example, alt "Japanese sweets" may bother to judge whether it is "imaged" the word "Japanese sweets" or "a picture of Japanese sweets".

There are images of graphs and charts, but there is alt that explains what graphs and charts it is (e.g. "Sales graph of June, July, August"). Level A does not ask for a detailed description of the value of the graph, but of course there is a description of the value in the range that is possible. It is also good to have a table marked up with table nearby.

Google Map is difficult for visually impaired people to handle, but explains "Google Map. Zoom and moveable map".

There is an image of the map, it is difficult for the visually impaired to handle, but there is alt "map". However, if there is a text explanation etc. in the vicinity, alt can be empty but it will not be a fatal barrier. If there is no route explanation in the vicinity, and it is not clearly stating that it is an image of the map, you can not even ask people, so be sure to correct it as it is a barrier.

The gif animation that explains how to operate some kind of instruments is difficult for the visually impaired, but it is difficult to understand for the visually impaired, but by describing the function by assigning alternative text such as "Animation explaining how to operate the instrument" . However, considering that 1-2-1d of the same level A is met in the end, it is better to try to explain as much as possible.

If you are providing a speech in speech, this item is not applicable even if you substitute such alternative text of speech as "voice of the speech." By preparing transcribed text, it becomes "able to handle functions", so in the case of such speech, prepare transcribed text.

It is a hearing-dependent test such as a hearing test.

The image of the flower is displayed and it is an image that asks "Which part is calyx?" It clearly indicates that it is an image for testing purposes.

If you prepare transcribed text with these images, movies and sounds, it will not be a test, so you will explain the purpose of the content with alternative text.

"This sound is an example of sounds that people feel fear", "When looking at it is an image that loses sense of equilibrium", you explain that.

It is almost impossible to transcribe "specific senses" and reproduce them in text, so these are out of the scope of accessibility checks.

Principle Perceivable Information and user interface components must be presentable to users in ways they can perceive.
Guideline Text Alternatives Provide text alternatives for any non-text content so that it can be changed into other forms people need, such as large print, braille, speech, symbols or simpler language.
Criterion Non-text Content
(1.1.1 A)
For all non-textual content presented to users, textual substitutions are provided that serve equivalent purposes.

URL of Techniques for WCAG 2.0