LayoutTests/mathml/arbitrary-markup.html

<html xmlns='http://www.w3.org/1999/xhtml'>
<head>
    <title>MathML: inserting arbitrary markup</title>
    <script>
        if (window.testRunner)
        testRunner.dumpAsText();
    </script>
</head>
<body>
<table>
    <tr>
        <td><math id="math"></math></td>
    </tr>
    <tr>
        <td>
            <math xmlns="http://www.w3.org/1998/Math/MathML">
                <msub>
                    <mi id="mi1">a</mi>
                    <mi id="mi2">b</mi>
                </msub>
            </math>
        </td>
    </tr>
</table>
<script>
var elem = document.getElementById("mi2"); 
var parent = elem.parentNode;
var new_elem = document.createElement("wbr");
parent.insertBefore(new_elem, elem);
node = document.getElementById("math").appendChild(document.createElement("object")).lastElementChild;
elem = document.getElementById("mi1"); 
parent = elem.parentNode;
new_elem = document.createElement("strong");
parent.insertBefore(new_elem, elem);
parent.removeChild(elem);
</script>
</body>
</html>