<html>
<body>
    <script src="../../resources/js-test-pre.js"></script>
    <script>
        description('Tests that DOM timers gets throttled on hidden pages once they reach the max nesting level');
        jsTestIsAsync = true;

        let timerCount = 0;
        let isPageVisible = true;
        const timeoutInterval = 10;
        const maxNestingLevel = 5;
        let timerHandle = 0;

        function testTimer()
        {
            ++timerCount;

            timerHandle = setTimeout(testTimer, timeoutInterval);
            if (!isPageVisible && timerCount >= maxNestingLevel) {
                shouldBeTrue("internals.isTimerThrottled(timerHandle)");
                testRunner.resetPageVisibility();
                clearTimeout(timerHandle);
                finishJSTest();
                return;
            } else
                shouldBeFalse("internals.isTimerThrottled(timerHandle)");

            if (timerCount == 1) {
                testRunner.setPageVisibility("hidden");
                isPageVisible = false;
            }
        }

        function runTest()
        {
            if (!window.testRunner) {
                debug('This test requires testRunner');
                return;
            }
            testRunner.overridePreference("WebKitHiddenPageDOMTimerThrottlingEnabled", 1);

            timerHandle = setTimeout(testTimer, timeoutInterval);
            shouldBeFalse("internals.isTimerThrottled(timerHandle)");
        }
        onload = function() {
            runTest();
        };
    </script>
    <script src="../../resources/js-test-post.js"></script>
</body>
</html>