<!DOCTYPE html>
<html>
<head>
  <script>
    function tweak(){
      document.body.innerHTML="fuzz"
    }
  </script>
</head>
<body onload="tweak()">
  <svg xmlns="http://www.w3.org/2000/svg">
    <text>
      <foreignObject requiredFeatures="foo">
        <svg style="position: absolute;"/>
      </foreignObject>
    </text>
  </svg>
</body>
</html>