- Success Criterion 1.4.1
- Conformance level A
- W3C reference F81
Required or Error Fields Marked Only by a Red Border
1.4.1 — Use of Color
Scenario
Setting
A car-rental site's checkout flow
What’s wrong
Required fields or fields with errors are marked by color only (red border) — colorblind and screen reader users can't tell which field is the problem.
Example
<span class="required-field"></span> <!-- red asterisk only -->Why it matters
People with color-vision deficiency, low vision, or constrained viewing conditions such as strong glare.
How to test
Trigger a form error in grayscale: if the only change is a red border/text with no icon, symbol, or text label, it fails.
How to fix
Mark required/error fields with text or an icon plus a programmatic attribute — never color alone.
<span class="required-field">* <span class="visually-hidden">required</span></span>Color alone (a red dot or border) can't be the only signal — pair it with text or an icon plus label.
Outcome
On a car-rental site's checkout flow, this barrier is gone for people with color-vision deficiency — they can finish what they came here to do.
Who is affected
People with color-vision deficiency, low vision, or constrained viewing conditions such as strong glare.
Learn more
- Understanding Understanding document (opens in a new tab)
- Technique Related technique (opens in a new tab)
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