<?xml version=“1.0” standalone=“yes”?> <svg xmlns=“www.w3.org/Graphics/SVG/svg-19990412.dtd” width=“4in” height=“3in”>

<desc>This example uses the switch element to provide a 
fallback graphical representation of an equation, if 
MathML is not supported.
</desc>

<!– The <switch> element will process the first child element

     whose testing attributes evaluate to true.-->
<switch>

<!– Process the MathML if the system-required attribute

     evaluates to true (i.e., the user agent supports MathML
     embedded within SVG). -->
<foreignobject system-required="http://www.w3.org/TR/REC-MathML-19980407" width="100" height="50">

<!– MathML content goes here –>

</foreignobject>

<!– Else, process the following alternate SVG.

     Note that there are no testing attributes on the <g> element.
     If no testing attributes are provided, it is as if there
     were testing attributes and they evaluated to true.-->
<g>

<!– Draw a red rectangle with a text string on top. –>

    <rect style="fill: red"/>
    <text>Formula goes here</text>
  </g>
</switch>

</svg>