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<html>
<head>
<meta charset="utf-8">
<script src="../../resources/js-test-pre.js"></script>
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<body>
<script>

description("This test checks the implementation of the element traversal APIs on Document as part of the ParentNode interface.");

function createEmptyDocument()
{
    var doc = document.implementation.createHTMLDocument();
    while (doc.firstChild) {
        doc.removeChild(doc.firstChild);
    }
    return doc;
}

debug('Test with no children');
var noChildren = createEmptyDocument();
shouldBe("noChildren.firstElementChild", "null");
shouldBe("noChildren.lastElementChild", "null");
shouldBe("noChildren.childElementCount", "0");

debug('Test with no element children');
var noElementChildren = createEmptyDocument();
noElementChildren.appendChild(document.createComment("comment but not an element"));

shouldBe("noElementChildren.firstElementChild", "null");
shouldBe("noElementChildren.lastElementChild", "null");
shouldBe("noElementChildren.childElementCount", "0");

debug('Test with elements');
var children = createEmptyDocument();
children.appendChild(document.createComment("first comment"));
var child = document.createElement('p');
children.appendChild(child);
children.appendChild(document.createComment("a comment"));

shouldBe("children.firstElementChild", "child");
shouldBe("children.lastElementChild", "child");
shouldBe("children.childElementCount", "1");

</script>
<script src="../../resources/js-test-post.js"></script>
</body>
</html>