Tape measure
From JSXGraph Wiki
The JavaScript code
var board = JXG.JSXGraph.initBoard('box', {boundingbox: [-1,3,3,-1], axis:true});
var p1 = board.create('point', [0,0]);
var p2 = board.create('point', [1,1]);
var p3 = board.create('point', [2,1]);
var tape = board.create('tapemeasure', [[0, 2], [2, 2]], {name:'dist'});
[[Category::Examples]] [[Category::Geometry]]