<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<html lang="en-US">
<head>
<title></title>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<style type="text/css">
body { font-family: "MarkA"; }
</style>
</head>
<body>
<div id="t" style="visibility:hidden; width: -moz-fit-content">ABC</div>
<script>
document.body.offsetWidth;
var n = document.getElementById("t");
var w = document.defaultView.getComputedStyle(n, "").width;
var h = document.defaultView.getComputedStyle(n, "").height;
var d = document.createElement("div");
d.style.width = w;
d.style.height = h;
d.style.backgroundColor = "green";
n.parentNode.removeChild(n);
document.body.appendChild(d);
</script>
</body>
</html>