1  <?xml version="1.0" standalone="yes"?>
 2  <svg xmlns="http://www.w3.org/Graphics/SVG/svg-19990412.dtd" width="4in" height="3in">
 3    <desc>This example uses the switch element to provide a 
 4    fallback graphical representation of an equation, if 
 5    MathML is not supported.
 6    </desc>
 7  <!-- The <switch> element will process the first child element
 8         whose testing attributes evaluate to true.-->
 9    <switch>
10  <!-- Process the MathML if the system-required attribute
11           evaluates to true (i.e., the user agent supports MathML
12           embedded within SVG). -->
13      <foreignobject system-required="http://www.w3.org/TR/REC-MathML-19980407" width="100" height="50">
14  <!-- MathML content goes here -->
15      </foreignobject>
16  <!-- Else, process the following alternate SVG.
17           Note that there are no testing attributes on the <g> element.
18           If no testing attributes are provided, it is as if there
19           were testing attributes and they evaluated to true.-->
20      <g>
21  <!-- Draw a red rectangle with a text string on top. -->
22        <rect style="fill: red"/>
23        <text>Formula goes here</text>
24      </g>
25    </switch>
26  </svg>