<?xml version="1.0" standalone="yes"?>

<smil>

  <body>

    <!-- The SMIL <switch> element will process the

         first child element which tests true and skip

         past all others. -->

    <switch>



      <!-- The system-required attribute tests to see if

           the user agent supports SVG. If true, then

           render the file drawing.svg. -->

      <ref system-required="http://www.w3.org/Graphics/SVG/svg-19990412.dtd" 

           type="image/svg" src="drawing.svg" />



      <!-- Else, render the alternate image. -->

      <img src="alternate_image.jpg" />

    </switch>

  </body>

</smil>





