Highlighting the Line chart

By using two lines - the second with a smaller linewidth than the first, but using the same values as the first - the second is drawn on top of the first.

This goes in the documents header:

<script src="RGraph.common.core.js"></script>
<script src="RGraph.common.dynamic.js"></script>
<script src="RGraph.line.js"></script>

Put this where you want the chart to show up:

<canvas id="cvs" width="600" height="250">
    [No canvas support]
</canvas>

This is the code that generates the chart: