chromium/third_party/blink/web_tests/fast/events/before-unload-in-multiple-subframes.html

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<body>
<p>This tests beforeunload event in multiple subframes. You should see PASS below:</p>
<pre id="log"></pre>
<script>

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

var log = document.getElementById('log');

function test(iframe) {
    if (iframe.done)
        return;
    iframe.done = true;
    iframe.contentWindow.location.href = 'resources/before-unload-in-subframe-child.html';
}

var numberOfBeforeUnloadInSubframes = 0;
var numberOfFrames = 3;

function logError() {
    log.innerHTML = 'FAIL: ' + numberOfBeforeUnloadInSubframes + ' beforeunload events are fired but expected ' + numberOfFrames + ' events';
}

logError();

function fired(contentWindow) {
    numberOfBeforeUnloadInSubframes++;
    if (numberOfBeforeUnloadInSubframes == numberOfFrames) {
        log.innerHTML = 'PASS';
        if (window.testRunner)
            testRunner.notifyDone();
    }
    else
        logError();
    contentWindow.frameElement.fired = true;
}

</script>
<iframe onload="test(this)" src="resources/before-unload-in-subframe-child.html"></iframe>
<iframe onload="test(this)" src="resources/before-unload-in-subframe-child.html"></iframe>
<iframe onload="test(this)" src="resources/before-unload-in-subframe-child.html"></iframe>
</body>
</html>