LayoutTests/accessibility/language-attribute-change.html

<html>
<head>
<meta http-equiv='content-language' content='de' />
<script src="../resources/accessibility-helper.js"></script>
<script src="../resources/js-test.js"></script>
</head>
<body>

<!-- It is intentional that #wrapper is an ignored element, proving that we still respect lang attributes on ignored objects. -->
<div id="wrapper">
    <div id="content" lang="en">Hello World!</div>
</div>

<script>
var output = "This test ensures the language attribute is correct even after dynamic page changes.\n";
if (window.accessibilityController) {
    window.jsTestIsAsync = true;

    var content = document.getElementById("content");
    var accessibleContent = accessibilityController.accessibleElementById("content");
    output += expect("accessibleContent.language", "'AXLanguage: en'");

    content.setAttribute("lang", "es");
    setTimeout(async function() {
        output += await expectAsync("accessibleContent.language", "'AXLanguage: es'");

        content.removeAttribute("lang");
        document.getElementById("wrapper").setAttribute("lang", "fr");
        output += await expectAsync("accessibleContent.language", "'AXLanguage: fr'");

        document.getElementsByTagName("head")[0].innerHTML += "";
        document.getElementById("wrapper").removeAttribute("lang");
        // Fallback to the meta tag content language.
        output += await expectAsync("accessibleContent.language", "'AXLanguage: de'");

        debug(output);
        finishJSTest();
    }, 0);
}
</script>
</body>
</html>