Cubic spline interpolation

Constructs a cubic spline through given points. Points can be added by clicking on "Add point".

References

• http://en.wikipedia.org/wiki/Spline_interpolation

The underlying JavaScript code

var board = JXG.JSXGraph.initBoard('box', {originX: 250, originY: 250, unitX: 50, unitY: 25, axis:true});
var p = [];
p[0] = board.create('point', [-1,2], {style:6});
p[1] = board.create('point', [0,-1], {style:6});
p[2] = board.create('point', [1,0], {style:6});
p[3] = board.create('point', [2,1], {style:6});

var c = board.create('spline', p, {strokeWidth:3});

var g = board.create('glider', [1.5,0,c], {name:'',style:8});
var t = board.create('tangent', [g], {dash:2,strokeColor:'#aa0000'});
     
function addPoint() {
    p.push(board.create('point',[(Math.random()-0.5)*10,(Math.random()-0.5)*3],{style:6}));
    board.update();
}