Another dynamically updating Line chart (using two canvas tags)

This chart uses two canvas tags - one for the background and axes and another for the scrolling Line. This saves on the cost of drawing each frame - but by how much and whether it's noticeable is dependent on many factors.

This goes in the documents header:

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

Put this where you want the chart to show up:

<div style="position: relative; width: 600px; height: 250px">
    <canvas id="cvs1" width="600" height="250" style="position: absolute; top: 0; left: 0"  data-l="false">[No canvas support]</canvas>
    <canvas id="cvs2" width="600" height="250"  style="position: absolute; top: 0; left: 0" data-l="false">[No canvas support]</canvas>
</div>

This is the code that generates the chart: