1  <?xml version="1.0" standalone="yes"?>
 2  <svg width="4in" height="3in"
 3   xmlns = 'http://www.w3.org/Graphics/SVG/svg-19990412.dtd'>
 4    <desc>This example uses the switch element to provide a 
 5    fallback graphical representation of an equation, if 
 6    MathML is not supported.
 7    </desc>
 8    <!-- The <switch> element will process the first child element
 9         whose testing attributes evaluate to true.-->
10    <switch>
11  
12      <!-- Process the MathML if the system-required attribute
13           evaluates to true (i.e., the user agent supports MathML
14           embedded within SVG). -->
15      <foreignobject 
16         system-required="http://www.w3.org/TR/REC-MathML-19980407" 
17         width="100" height="50">
18        <!-- MathML content goes here -->
19      </foreignobject>
20  
21      <!-- Else, process the following alternate SVG.
22           Note that there are no testing attributes on the <g> element.
23           If no testing attributes are provided, it is as if there
24           were testing attributes and they evaluated to true.-->
25      <g>
26        <!-- Draw a red rectangle with a text string on top. -->
27        <rect style="fill: red"/>
28        <text>Formula goes here</text>
29      </g>
30  
31    </switch>
32  </svg>