This goes in the documents header:
<script src="RGraph.common.core.js"></script> <script src="RGraph.segmented.js"></script>Put this where you want the chart to show up:
<canvas id="cvs" width="300" height="300">[No canvas support]</canvas>
<p>
<button onclick="update()" style="font-size: 26pt; cursor: pointer">Adjust meter</button>
</p>
This is the code that generates the chart: