encoding/json-document-utf8.html

<!DOCTYPE html>
<meta charset="windows-1251">
<title>JSON documents are decoded as UTF-8 by default</title>
<link rel="help" href="https://datatracker.ietf.org/doc/html/rfc8259#section-8.1">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<body>
<script>
const utf8 = '{"text":"\u2603\u00e9"}';

function loadJSON(query) {
  return new Promise((resolve, reject) => {
    const frame = document.createElement("iframe");
    frame.onload = () => {
      const text = frame.contentDocument.body.textContent;
      frame.remove();
      resolve(text);
    };
    frame.onerror = () => { frame.remove(); reject(new Error("load failed")); };
    frame.src = "resources/json-charset.py" + query;
    document.body.appendChild(frame);
  });
}

promise_test(async () => {
  assert_equals(await loadJSON(""), utf8);
}, "application/json with no charset is decoded as UTF-8 under a windows-1251 parent frame");

promise_test(async () => {
  assert_equals(await loadJSON("?charset=utf-8"), utf8);
}, "application/json;charset=utf-8 is decoded as UTF-8");

promise_test(async () => {
  assert_equals(await loadJSON("?type=text/json"), utf8);
}, "text/json with no charset is decoded as UTF-8");

promise_test(async () => {
  assert_not_equals(await loadJSON("?charset=windows-1251"), utf8);
}, "application/json;charset=windows-1251 honors the explicit charset");
</script>
</body>