Bas Wenneker has written Plotr, a charting engine in Prototype that uses canvas. Example PLAIN TEXT JAVASCRIPT:   var dataset = {                 'myFirstDataset': [[0, 1], [1, 0.8], [2, 2.3], [3, 1.3], [4, 2.56]],                 'mySecondDataset': [[0, 0.5], [1, 0.5], [2, 2], [3, 1], [4, 1.4]]