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