LayoutTests/http/tests/xmlhttprequest/if-modified-since-0.html

<script>

if (window.testRunner) {
    testRunner.dumpAsText();
    testRunner.waitUntilDone();
}

var req1 = new XMLHttpRequest();
req1.onreadystatechange = function () {
    if (this.readyState == 4) {
        alert(internals.xhrResponseSource(req1) == "Network" ? "PASS" : "FAIL");
        var req2 = new XMLHttpRequest();
        req2.onreadystatechange = function () {
            if (this.readyState == 4) {
                alert(internals.xhrResponseSource(req2) == "Network" ? "PASS" : "FAIL");
                if (window.testRunner)
                    testRunner.notifyDone();
            }
        }
        req2.open("GET", "resources/get.txt");
        req2.setRequestHeader("If-Modified-Since", "0");
        req2.send(null);
    }
};
req1.open("GET", "resources/get.txt");
req1.setRequestHeader("If-Modified-Since", "0");
req1.send(null);

</script>