// Define the id of your board in BOARDID
JXG.Options.axis.strokeColor = '#cccccc';
const board = JXG.JSXGraph.initBoard(BOARDID, {
boundingbox: [-15, 10, 15, -10],
axis: true
});
var b = board.create('slider', [[-14, 8], [-4, 8], [-10, 2.10, 10]], {name: 'a', point1: {frozen: true}, point2: {frozen: true}});
var a = board.create('slider', [[-14, 7], [-4, 7], [-10, -9.52, 10]], {name: 'b', point1: {frozen: true}, point2: {frozen: true}});
var c = board.create('implicitcurve', [
(x, y) => -(y**2) + x**3 + a.Value() * x + b.Value()
], {
strokeWidth: 3, strokeColor: JXG.palette.red
});