SVG parameter dynamism

<?xml version="1.0" standalone="no"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
<svg xmlns="http://www.w3.org/2000/svg" width="6cm" height="5cm" viewBox="0 0 600 500" version="1.1" onload="set_col(evt)">
    <desc>Example script, set color by URI parameter
  </desc>
    <!-- ECMAScript to change the radius with each click -->
    <script type="application/ecmascript"><![CDATA[

    function set_col(evt){
        // debugger
        var params = document.location.search.slice(1).split('&')
        for (i = 0; i < params.length; i++){
            if (params[i].indexOf("color=")==0){
                document.getElementById("cc").setAttribute('fill',params[i].split('=')[1])
            }
        }
    }

  ]]></script>
    <!-- Outline the drawing area with a blue line -->
    <rect x="1" y="1" width="598" height="498" fill="none" stroke="blue"/>
    <!-- Act on each click event -->
    <circle id="cc" cx="300" cy="225" r="200" fill="blue"/>
</svg>