sible overflow.")

// no overflow property set to `visible` => pot. scrollable
test(function() {
    document.body.style.overflowY = "scroll";
    assert_equals(document.body.style.overflowY, "scroll");
    document.documentElement.style.overflowY = "scroll";
    assert_equals(document.documentElement.style.overflowY, "scroll");

    assert_greater_than(window.innerHeight, 400, "Window not large enough for valid test run.");
    assert_not_equals(document.body.scrollHeight, window.innerHeight);

    var ele