Use the MediaWiki extension for JSXGraph

Download the MediaWiki extension http://www.mediawiki.org/wiki/Extension:JSXGraph here.

<jsxgraph height="500" width="600" board="board" box="mybox">
board = JXG.JSXGraph.initBoard('mybox', {boundingbox: [-10, 10, 14, -10]});
var a = board.create('slider', [[1,8],[5,8],[0,1,4]]);
var b = board.create('slider', [[1,9],[5,9],[0,0.25,4]]);
var c = board.create('curve', [function(phi){return a.Value()+b.Value()*phi; }, [0, 0], 0, 8*Math.PI],
{curveType:'polar', strokewidth:4});      
</jsxgraph>