<meta name=viewport content="width=device-width">
<div style="border: solid; -webkit-writing-mode: horizontal-bt; inline-size: 200px; block-size: 400px;
    font-size: 36px; line-height: 2;
">
    Lorem ipsum dolor <span id="target">sit</span> amet consectetur adipiscing elit.
</div>
<p id="result">
    FAIL: Test did not run.
</p>
<script>
    if (window.testRunner) {
        testRunner.dumpAsText();
    }
    var target = document.getElementById("target");
    var range = document.createRange();
    range.selectNode(target.firstChild);
    var textTop = range.getClientRects()[0].top;
    range.selectNode(target);
    var spanTop = range.getClientRects()[0].top;
    if (spanTop === textTop)
        result.innerText = "PASS";
    else
        result.innerText  = "FAIL: Text top was " + textTop + " but expected " + spanTop + ".";
</script>