This technique relates to Success Criterion 1.1.1: Non-text Content (Failure).
The objective of this failure condition is to avoid the use of ASCII art when a text alternative is not provided. Although ASCII art is implemented as a character string, its meaning comes from the pattern of glyphs formed by a visual presentation of that string, not from the text itself. Therefore ASCII art is non-text content and requires a text alternative. Text alternatives, or links to them, should be placed near the ASCII art in order to be associated with it.
Example 1: ASCII Art chart without a text alternative
The following ASCII art chart lacks a text alternative and therefore does not meet Success Criterion 1.1.1. Note this failure example does in fact cause this page to fail, but you may skip over the example.
<pre> % __ __ __ __ __ __ __ __ __ __ __ __ __ __ 100 | * | 90 | * * | 80 | * * | 70 | @ * | 60 | @ * | 50 | * @ * | 40 | @ * | 30 | * @ @ @ * | 20 | | 10 | @ @ @ @ @ | 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 Flash frequency (Hz) </pre>
- Access a page with ASCII art.
- For each instance of ASCII art, check that it has a text alternative.
- If check #2 is false, then this failure condition applies and the content fails this Success Criterion.