Intersection of circles

The underlying JavaScript code

var board = JXG.JSXGraph.initBoard('jxgbox', {
    axis:true,
    boundingbox:[-5, 5, 5, -5]
});

var c1 = board.create('circle', [[-1, 1.5], 3]);
var c2 = board.create('circle', [[1, -1.5], 3]);

var clip_path = board.create('curve', [[], []], {strokeWidth: 2, fillColor: 'yellow', fillOpacity: 0.3});
clip_path.updateDataArray = function() {
    var a = JXG.Math.Clip.intersection(c1, c2, this.board);

    this.dataX = a[0];
    this.dataY = a[1];
};
board.update();