// Define the id of your board in BOARDID
const board = JXG.JSXGraph.initBoard(BOARDID, {
boundingbox: [-1, 5, 5, -1],
axis: true
});
// Create three circles
var p1 = board.create('point', [1, 1]);
var p2 = board.create('point', [3, 0]);
var c1 = board.create('circle', [p1, p2], {strokeWidth:2});
var p3 = board.create('point', [4, 1]);
var p4 = board.create('point', [2, 0]);
var c2 = board.create('circle', [p3, p4], {strokeWidth:2});
var p5 = board.create('point', [2.5, 4.5]);
var p6 = board.create('point', [-0.5, 4.5]);
var c3 = board.create('circle', [p5, p6], {strokeWidth:2});
// The curve a1 is the intersection of c1 and c2
var a1 = board.create('curveintersection', [c1, c2], {visible: false});
// Intersect a1 and c2
var a2 = board.create('curveintersection', [a1, c3], {
strokeColor: 'red',
strokeWidth: 4,
fillColor: 'yellow',
fillOpacity: 0.3,
highlightFillColor: 'blue',
highlightFillOpacity: 0.3,
hasInnerPoints: true
});