Table 6.
A List of All Known Problems Detected by AChecker at Level AA, Sorted from The Most Recurring to The Least
| Category | Guideline | Success criteria | Websites affected | Error frequency | Error percentage % |
|---|---|---|---|---|---|
| Perceivable | 1.4 |
i (italic) element used Success Criteria 1.4.4 Resize text (AA) |
13 | 415 | 37.39 |
| Perceivable | 1.1 |
Img element missing alt attribute Success Criteria 1.1.1 Non-text Content |
9 | 253 | 22.79 |
| Operable | 2.4 |
Anchor contains no text Success Criteria 2.4.4 Link Purpose (In Context) |
6 | 108 | 9.73 |
| Perceivable | 1.4 |
The contrast between the color of selected link text and its background is not sufficient to meet WCAG2.0 Level AA Success Criteria 1.4.3 Contrast (Minimum) (AA) |
2 | 90 | 8.11 |
| Perceivable | 1.1 |
Image used as anchor is missing valid Alt text Success Criteria 1.1.1 Non-text Content |
7 | 76 | 6.85 |
| Perceivable | 1.4 |
The contrast between the color of text and its background for the element is not sufficient to meet WCAG2.0 Level AA Success Criteria 1.4.3 Contrast (Minimum) (AA) |
4 | 61 | 5.50 |
| Understandable | 3.3 |
Label text is empty Success Criteria 3.3.2 Labels or Instructions |
5 | 26 | 2.34 |
| Perceivable | 1.3 |
Input element, type of "text", missing an associated label Success Criteria 1.3.1 Info and Relationships |
5 | 14 | 1.26 |
| Perceivable | 1.3 |
Input element, type of "text", has no text in label Success Criteria 1.3.1 Info and Relationships |
5 | 11 | 0.99 |
| Understandable | 3.1 |
Document language not identified Success Criteria 3.1.1 Language of Page |
4 | 10 | 0.90 |
| Understandable | 3.1 |
Document has invalid language code Success Criteria 3.1.1 Language of Page |
4 | 10 | 0.90 |
| Robust | 4.1 |
Id attribute is not unique Success Criteria 4.1.1 Parsing |
4 | 6 | 0.54 |
| Operable | 2.4 |
title element is empty Success Criteria 2.4.2 Page Titled |
1 | 5 | 0.45 |
| Operable | 2.4 |
Header nesting—header following h2 is incorrect Success Criteria 2.4.6 Headings and Labels (AA) |
3 | 4 | 0.36 |
| Operable | 2.1 |
onmousedown event missing onkeydown event Success Criteria 2.1.1 Keyboard |
0 | 3 | 0.27 |
| Perceivable | 1.3 |
input element, type of "checkbox", has no text in label Success Criteria 1.3.1 Info and Relationships |
1 | 3 | 0.27 |
| Perceivable | 1.3 |
Textarea element missing an associated label Success Criteria 1.3.1 Info and Relationships |
2 | 3 | 0.27 |
| Perceivable | 1.1 |
input element has alt attribute Success Criteria 1.1.1 Non-text Content |
1 | 2 | 0.18 |
| Operable | 2.4 |
Document missing title element Success Criteria 2.4.2 Page Titled |
1 | 2 | 0.18 |
| Operable | 2.4 | Header nesting—header following h1 is incorrect Success Criteria 2.4.6 Headings and Labels (AA) | 1 | 1 | 0.09 |
| Perceivable | 1.1 | Embed element missing noembed element Success Criteria 1.1.1 Non-text Content | 1 | 1 | 0.09 |
| Perceivable | 1.3 |
Input element, type of "password", missing an associated label Success Criteria 1.3.1 Info and Relationships |
1 | 1 | 0.09 |
| Perceivable | 1.3 |
Input element, type of "checkbox", missing an associated label Success Criteria 1.3.1 Info and Relationships |
1 | 1 | 0.09 |
| Perceivable | 1.3 |
Input element, type of "password", has no text in label Success Criteria 1.3.1 Info and Relationships |
1 | 1 | 0.09 |
| Operable | 2.1 |
Script not keyboard accessible—onmouseout missing onblur Success Criteria 2.1.1 Keyboard |
1 | 1 | 0.09 |
| Operable | 2.1 |
Onmouseover event handler missing onfocus event handler Success Criteria 2.1.1 Keyboard |
1 | 1 | 0.09 |
| Understandable | 3.1 |
Right to left reading order not marked or marked incorrectly Success Criteria 3.1.1 Language of Page |
1 | 1 | 0.09 |
| Total | 1110 | 100 |