Interpolation: Neville's algorithm
From JSXGraph Wiki
References
The underlying JavaScript code
<link rel="stylesheet" type="text/css" href="http://jsxgraph.uni-bayreuth.de/distrib/jsxgraph.css" />
<script type="text/javascript" src="http://jsxgraph.uni-bayreuth.de/distrib/prototype.js"></script>
<script type="text/javascript" src="http://jsxgraph.uni-bayreuth.de/distrib/jsxgraphcore.js"></script>
<div id="box" class="jxgbox" style="width:600px; height:400px;"></div>
board = JXG.JSXGraph.initBoard('box', {axis:true, originX: 250, originY: 250, unitX: 50, unitY: 50});
var p = [];
p[0] = board.createElement('point', [-1,2], {style:6});
p[1] = board.createElement('point', [3,-1], {style:6});
p[2] = board.createElement('point', [2,1], {style:6});
graph = board.createElement('curve', board.neville(p),{strokeWidth:5,strokeOpacity:0.5});
g = board.createElement('glider', [graph]);
t = board.createElement('tangent', [g],{dash:1,strokeColor:'green'});
function addPoint() {
p.push(board.createElement('point',[(Math.random()-0.5)*10,(Math.random()-0.5)*3],{style:6}));
board.update();
}