third_party/web_platform_tests/XMLHttpRequest/send-network-error-sync-events.sub.htm

<!DOCTYPE html>
<html>
<head>
    <link rel="help" href="https://xhr.spec.whatwg.org/#infrastructure-for-the-send()-method" data-tested-assertations="following::dt[4] following::dd[4]/p" />
    <link rel="help" href="https://xhr.spec.whatwg.org/#network-error" data-tested-assertations=".." />
    <link rel="help" href="https://xhr.spec.whatwg.org/#request-error" data-tested-assertations="following::ol[1]/li[4] following::ol[1]/li[5]" />
    <script src="/resources/testharness.js"></script>
    <script src="/resources/testharnessreport.js"></script>
    <title>XmlHttpRequest: The send() method: Throw a "throw an "NetworkError" exception when Network error happens (synchronous flag is set)</title>
</head>

<body>
    <div id="log"></div>

    <script type="text/javascript">
        test(function()
        {
            var xhr = new XMLHttpRequest();

            xhr.open("POST", "http://nonexistent-origin.{{host}}}:{{ports[http][0]}}", false);

            assert_throws("NetworkError", function()
            {
                xhr.send("Test Message");
            });
            assert_equals(xhr.readyState, 4)

            xhr.open("GET", "data:text/html;charset=utf-8;base64,PT0NUWVBFIGh0bWw%2BDQo8", false);

            assert_throws("NetworkError", function()
            {
                xhr.send("Test Message");
            });
            assert_equals(xhr.readyState, 4)

        });
    </script>
</body>
</html>