css/css-flexbox/auto-margins-001.html

<!DOCTYPE html>
<html>
<head>
<title>CSS Test: Aligning with auto margins</title>
<link href="support/flexbox.css" rel="stylesheet">
<link rel="stylesheet" type="text/css" href="/fonts/ahem.css" />
<link rel="author" title="Google Inc." href="http://www.google.com/">
<link rel="help" href="https://drafts.csswg.org/css-flexbox/#auto-margins">
<link rel="match" href="auto-margins-001-ref.html">
<style>

#circles, #circles div {
    display: flex;
    width: -webkit-calc(100% - 4em);
    width: calc(100% - 4em);
    height: -webkit-calc(100% - 4em);
    height: calc(100% - 4em);
    border: 1em solid blue;
    border-radius:50%;
    margin: auto;
}

#circles { width:9em; height:9em; }

</style>
</head>
<body>
<p>These tests are from the spec: <a href="http://dev.w3.org/csswg/css3-flexbox/#auto-margins">http://dev.w3.org/csswg/css3-flexbox/#auto-margins</a>.</p>

<p>The black rectangle should be centered vertically and horizontally.</p>
<div class="flexbox" style="width: 4em; height: 4em; background: silver">
  <p id="ok" style="margin: auto; font-family: Ahem;">OK</p>
</div>

<div class="flexbox" style="width: 4em; height: 4em; margin-top: 10px; background: silver; writing-mode: vertical-rl">
  <p id="okVertical" style="margin: auto; font-family: Ahem;">OK</p>
</div>

<p>You should see 3 blue concentric circles.</p>
<div id="circles"><div><div></div></div></div>

<p id="log">The computed style of each margin should not be 0.</p>
<script>
var okStyle = getComputedStyle(document.getElementById('ok'));
document.getElementById("log").innerHTML += "<br>OK: " +
    ((parseInt(okStyle.marginTop) && parseInt(okStyle.marginRight) && parseInt(okStyle.marginBottom) && parseInt(okStyle.marginLeft)) ? "PASS" : "FAIL");

var okVerticalStyle = getComputedStyle(document.getElementById('okVertical'));
document.getElementById("log").innerHTML += "<br>Vertical OK: " +
    ((parseInt(okVerticalStyle.marginTop) && parseInt(okVerticalStyle.marginRight) && parseInt(okVerticalStyle.marginBottom) && parseInt(okVerticalStyle.marginLeft)) ? "PASS" : "FAIL");
</script>
</body>
</html>