http/tests/xmlhttprequest/xmlhttprequest-sync-vs-async-assertion-failure.html

<html><head></head><body>

<p>You should see "PASS" once:</p>

<script type="text/javascript">
if (window.testRunner)
    testRunner.dumpAsText();

var xhr;

if (window.XMLHttpRequest) {
    xhr = new XMLHttpRequest();
} else {
    try {
        xhr = new ActiveXObject("Msxml2.XMLHTTP");
    } catch (ex) {
        xhr = new ActiveXObject("Microsoft.XMLHTTP");
    }
}

xhr.open("GET", "resources/1251.html", false);
xhr.onreadystatechange = function () {
    try {
        xhr.open("GET", "resources/1251.html", true);
        xhr.send(null);
    } catch (ex) {
    }
}

xhr.send(null);

document.write("PASS");

</script>

</body></html>