Polynomial regression II

Here are 30 randomly distributed points. The range of these points can be adjusted by the slider 'scale'. Through these points a regression polynomial is computed. The degree of this polynomial can be adjusted by the slider 'degree'.

The underlying JavaScript code

brd = JXG.JSXGraph.initBoard('jxgbox', {boundingbox:[-2, 100, 220, -70], grid: false, axis:true});
brd.suspendUpdate();
deg = brd.create('slider',[[10,90],[100,90],[1,1,10]],{name:'degree',snapWidth:1});     
s = brd.create('slider',[[10,70],[100,70],[0,1,3]],{name:'scale'});     
pointlist = [];
for (i=0; i<30;i++) {
    pointlist.push(brd.create('point', [function() { return 200*Math.random(); }, function() { return s.Value()*30*Math.random()+20;}], { style:4, strokecolor:"#0000a0", name:" "})); 
}
brd.unsuspendUpdate();

regression = JXG.Math.Numerics.regressionPolynomial(deg,pointlist); 
reg = brd.create('functiongraph',[regression],{strokeColor:'green'});     
t = brd.create('text',[20,-40,
            function(){ return "r(x) = " + regression.getTerm();}
            ],
            {strokeColor:'black',fontSize:'14px'});