set stroke color of polygon

HTML

<script src="http://jsxgraph.uni-bayreuth.de/distrib/jsxgraphcore.js"></script>
<script src="http://jsxgraph.uni-bayreuth.de/distrib/jsxgraph,css"></script>
<div id="box"></div>

CSS

#box {
    width:500px;
    height:500px;
    margin: 0 4em 1em 0;
    float: left;
}

JavaScript

var board = JXG.JSXGraph.initBoard('box', {
        boundingbox: [-4,4,4,-4], 
        keepaspectratio: true, 
    });

var p1 = board.create('point',[0,0]);
var p2 = board.create('point',[1,3]);
var p3 = board.create('point',[3,2]);
var p4 = board.create('point',[-2,2]);

board.create('polygon', [p1, p2, p3], {strokeColor: 'pink', borders: {strokeColor: 'pink'}});
board.create('polygon', [p1, p2, p4], {borders: {colors: ['white', 'white', 'white']}});