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 = board.create('curveintersection', [c1, c2], 
          { strokeWidth: 2, fillColor: 'yellow', fillOpacity: 0.3 });