WCAG：通用的法律衡量标准

From the U.S. to the EU to Canada and Australia, accessibility laws keep converging on a single technical reference: WCAG.

The Web Content Accessibility Guidelines come from the W3C, the same standards body behind HTML and CSS, which gives them broad credibility.

WCAG breaks down into discrete success criteria that are pass or fail. Laws love this because it turns a vague duty into checkable requirements.

The guidelines define three levels. Almost every law points specifically at Level AA, treating AAA as aspirational and A alone as too weak.

WCAG 2.1 added mobile and low-vision criteria, and 2.2 added more. Laws often reference a specific version, so check which one applies.

Each 2.x release is backward compatible: meeting 2.2 AA means you also meet 2.1 and 2.0 AA, which simplifies multi-jurisdiction compliance.

Writing a fresh technical spec per country is impractical, so legislators reference WCAG rather than reinvent it, creating a shared global yardstick.

Regional norms like the EU EN 301 549 and others deliberately incorporate WCAG, so the same criteria sit underneath many different statutes.

The practical upshot: if you build to WCAG 2.2 AA, you are aligned with the core of most accessibility laws worldwide at the same time.

Passing automated WCAG checks is not the same as conformance; many criteria need human judgment and real assistive-tech testing.

WCAG AA is a legal minimum, not the finish line. Real users may still hit barriers, so usability testing should continue past it.

Recall why laws lean on one spec.

Laws converge on WCAG AA because its testable criteria are reusable and stable. Build to 2.2 AA and you align with most of them at once.