How to create a conic gradient in SVG (needs JavaScript)

conic-gradient.svg

<?xml version="1.0" standalone="yes"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd"> 
<svg viewBox="0 0 100 100" version="1.1" onload="makeGradient();">
    <script>
        function makeGradient() {
            var root = document.rootElement;
            var i = 256;
            var circle;
            var angle;
            for (; i--;) {
                angle = i * Math.PI / 128;
                circle = document.createElementNS("http://www.w3.org/2000/svg", "circle");
                circle.setAttribute("cx", 50 - Math.sin(angle) * 45);
                circle.setAttribute("cy", 50 - Math.cos(angle) * 45);
                circle.setAttribute("r", "5");
                circle.setAttribute("fill", "rgb(" + i + ", " + i + ", " + i + ")");
                root.appendChild(circle);
            }
        }
    </script>
</svg>

From this old post: http://stackoverflow.com/questions/17149286/svg-polar-gradients