AfterAttributeValueUnquotedState:
<div id="console"></div>
<div>
    <div style="visibility:hidden">
        <p id=start</div>
    Start Tag: FAIL
</div>
<div>
    <div style="visibility:hidden">
        <p></p id=end</div>
    End Tag: FAIL
</div>
<script>
    var console = document.getElementById("console");
    if (!document.getElementById("start"))
        console.innerHTML += "Start Tag: PASS<br>";
    if (!document.getElementById("end"))
        console.innerHTML += "End Tag: PASS<br>";
</script>