A Scatter chart with the ability to add markers

You can click on the Scatter chart to add a red circle. When the circles are then clicked on nothing happens.

[No canvas support]

This goes in the documents header: 
<script src="RGraph.common.core.js"></script>
<script src="RGraph.common.dynamic.js"></script>
<script src="RGraph.common.circle.js"></script>
<script src="RGraph.drawing.circle.js"></script>
<script src="RGraph.scatter.js"></script>
Put this where you want the chart to show up: 
<canvas id="cvs" width="600" height="200">
    [No canvas support]
</canvas>
This is the code that generates the chart: