<html>
<head>
<style>
.lr { -webkit-writing-mode: vertical-lr; background-color:green; margin-left:auto; margin-right:auto; width:100px; height:100px; }
</style>
</head>
<body>
The green LR block should be centered horizontally within the black-bordered block.
<div style="width:300px; height:100px;border:2px solid black">
<div class="lr" id="test"></div>
</div>
<div id="console"></div>
<script>
if (window.testRunner)
    window.testRunner.dumpAsText();
test = document.getElementById("test");
rect = test.getBoundingClientRect();
if (rect.left != 110) {
  document.getElementById('console').innerHTML = "FAIL: The block should be at an x-offset of 100.";
  test.style.backgroundColor = 'red';
} else
  document.getElementById('console').innerHTML = "PASS: The block is in the correct position.";
</script>

</body>