Switch between visible layers in SVG

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!-- Created with Inkscape (http://www.inkscape.org/) -->

<svg
   xmlns:dc="http://purl.org/dc/elements/1.1/"
   xmlns:cc="http://creativecommons.org/ns#"
   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
   xmlns:svg="http://www.w3.org/2000/svg"
   xmlns="http://www.w3.org/2000/svg"
   xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
   width="200"
   height="200"
   id="svg2"
   version="1.1"
   inkscape:version="0.48.1 r9760"
   sodipodi:docname="Nytt dokument 1">
  <defs
     id="defs4" />
  <script type="application/ecmascript"> <![CDATA[
    var visibleLayer = 'layer1';
    function goToLayer(layer) {
    document.getElementById(visibleLayer).setAttribute('style', 'display: none');
    document.getElementById(layer).setAttribute('style', 'display: inline');
    visibleLayer = layer;
    }
  ]]> </script>
  <sodipodi:namedview
     id="base"
     pagecolor="#ffffff"
     bordercolor="#666666"
     borderopacity="1.0"
     inkscape:pageopacity="0.0"
     inkscape:pageshadow="2"
     inkscape:zoom="3.45"
     inkscape:cx="63.913043"
     inkscape:cy="100"
     inkscape:document-units="px"
     inkscape:current-layer="layer2"
     showgrid="false"
     inkscape:window-width="1440"
     inkscape:window-height="876"
     inkscape:window-x="0"
     inkscape:window-y="24"
     inkscape:window-maximized="1" />
  <metadata
     id="metadata7">
    <rdf:RDF>
      <cc:Work
         rdf:about="">
        <dc:format>image/svg+xml</dc:format>
        <dc:type
           rdf:resource="http://purl.org/dc/dcmitype/StillImage" />
        <dc:title></dc:title>
      </cc:Work>
    </rdf:RDF>
  </metadata>
  <g
     inkscape:label="layer1"
     inkscape:groupmode="layer"
     id="layer1"
     transform="translate(0,-852.36218)"
     style="display:inline">
    <rect
       style="fill:#000080;fill-opacity:1;stroke:none"
       id="rect2986"
       width="149.56522"
       height="108.4058"
       x="20"
       y="21.73913"
       transform="translate(0,852.36218)"
       onclick="goToLayer('layer2');" />
  </g>
  <g
     inkscape:groupmode="layer"
     id="layer2"
     inkscape:label="layer2"
     style="display:none">
    <path
       sodipodi:type="arc"
       style="fill:#000080;fill-opacity:1;stroke:none"
       id="path2988"
       sodipodi:cx="97.826088"
       sodipodi:cy="89.130432"
       sodipodi:rx="59.275364"
       sodipodi:ry="42.753624"
       d="m 157.10145,89.130432 a 59.275364,42.753624 0 1 1 -118.550726,0 59.275364,42.753624 0 1 1 118.550726,0 z"
       onclick="goToLayer('layer1');" />
  </g>
</svg>