scale axis

how to create an axis showing multiples of pi

HTML

<link rel="stylesheet" href="http://jsxgraph.uni-bayreuth.de/distrib/jsxgraph.css">
<script src="http://jsxgraph.uni-bayreuth.de/distrib/jsxgraphcore.js"></script>
<div id="jxgbox"></div>

CSS

#jxgbox {
    width: 700px;
    height: 700px;
}

JavaScript

var board = JXG.JSXGraph.initBoard('jxgbox', {boundingbox:[-5, 5, 5,-5], axis: {
    ticks: {scale: 12, scaleSymbol: '&pi;'}
}, grid: false});

var p = board.create('point', [1, 1], {label: {offsets: [10,10]}});