Get axe accessibility violations

Last updated: 25/05/2026

Resources:

• https://cdn.jsdelivr.net/npm/axe-core@4.11.0/axe.min.js 

/**
 *
 * // Simplest — full page, all WCAG violations
 * getAxeViolations returning $a11y
 * assert ${ $a11y.violationCount } equals "0"
 *
 * // Only critical/serious, skip a noisy widget
 * getAxeViolations("wcag2aa,wcag21aa", "#app", ".intercom-launcher", "serious") returning $a11y
 * assert ${ $a11y.impactCounts.critical } equals "0"
 * assert ${ $a11y.impactCounts.serious } equals "0"
 *
 * // Fast check — no per-node DOM detail in payload
 * getAxeViolations("wcag2aa", "", "", "", "true") returning $a11y
 * assert ${ $a11y.violationCount } equals "0"
 */

// Optional positional params:
//   tags         comma-separated axe tags. Default: "wcag2a,wcag2aa,wcag21a,wcag21aa,wcag22aa"
//   include      CSS selector to scope the audit, e.g. "#main"
//   exclude      CSS selector to skip,            e.g. ".third-party-widget"
//   minImpact    "minor" | "moderate" | "serious" | "critical" — filter floor
//   summaryOnly  "true" to omit per-node DOM detail (smaller payload)
//
// Returns: { url, timestamp, testEngine, violationCount, incompleteCount,
//            impactCounts:{critical,serious,moderate,minor}, violations:[...] }

const DEFAULT_TAGS   = ["wcag2a","wcag2aa","wcag21a","wcag21aa","wcag22aa","best-practice"];
const IMPACT_RANK    = { minor:1, moderate:2, serious:3, critical:4 };
const RUN_TIMEOUT_MS = 90000; // Virtuoso's 120s extension cap, script timeout limit

const optTags        = (typeof tags        !== "undefined") ? tags        : null;
const optInclude     = (typeof include     !== "undefined" && include     !== "") ? include     : null;
const optExclude     = (typeof exclude     !== "undefined" && exclude     !== "") ? exclude     : null;
const optMinImpact   = (typeof minImpact   !== "undefined" && minImpact)
                        ? String(minImpact).toLowerCase() : null;
const optSummaryOnly = (typeof summaryOnly !== "undefined")
                        && (summaryOnly === true || summaryOnly === "true");

if (typeof axe === "undefined" || typeof axe.run !== "function") {
  doneError("axe-core not loaded. Check the Resources URL on this extension.");
} else {
  const parseTags = t =>
    !t ? DEFAULT_TAGS
       : Array.isArray(t) ? t.filter(Boolean)
       : String(t).split(",").map(s => s.trim()).filter(Boolean);

  const buildContext = () => {
    if (!optInclude && !optExclude) return document;
    const ctx = {};
    if (optInclude) ctx.include = [optInclude];
    if (optExclude) ctx.exclude = [optExclude];
    return ctx;
  };

  const filterByImpact = vs => {
    if (!optMinImpact || !(optMinImpact in IMPACT_RANK)) return vs;
    const floor = IMPACT_RANK[optMinImpact];
    return vs.filter(v => IMPACT_RANK[v.impact || "minor"] >= floor);
  };

  const compactNodes = nodes => (nodes || []).map(n => ({
    target: n.target,
    html: (n.html || "").slice(0, 500),
    failureSummary: n.failureSummary
  }));

  const buildResult = results => {
    const filtered = filterByImpact(results.violations || []);
    const impactCounts = { critical:0, serious:0, moderate:0, minor:0 };
    filtered.forEach(v => {
      const k = v.impact || "minor";
      if (impactCounts[k] !== undefined) impactCounts[k]++;
    });
    return {
      url: results.url,
      timestamp: results.timestamp,
      testEngine: results.testEngine,
      violationCount: filtered.length,
      incompleteCount: (results.incomplete || []).length,
      impactCounts,
      violations: filtered.map(v => {
        const o = {
          id: v.id,
          impact: v.impact,
          help: v.help,
          helpUrl: v.helpUrl,
          description: v.description,
          tags: v.tags,
          nodeCount: (v.nodes || []).length
        };
        if (!optSummaryOnly) o.nodes = compactNodes(v.nodes);
        return o;
      })
    };
  };

  const runOptions = {
    resultTypes: ["violations", "incomplete"],
    runOnly: { type: "tag", values: parseTags(optTags) }
  };

  let timeoutId;
  const timeoutPromise = new Promise((_, reject) => {
    timeoutId = setTimeout(
      () => reject(new Error(`axe.run timed out after ${RUN_TIMEOUT_MS}ms`)),
      RUN_TIMEOUT_MS
    );
  });

  Promise.race([axe.run(buildContext(), runOptions), timeoutPromise])
    .then(results => {
      clearTimeout(timeoutId);
      done(JSON.stringify(buildResult(results)));
    })
    .catch(err => {
      clearTimeout(timeoutId);
      doneError("getAxeViolations failed: " +
        (err && err.message ? err.message : String(err)));
    });
}