A Line chart with alert() warnings prevented

This is a standard Line chart and the page also redefines the alert() function so that there are no warnings displayed. You simply need to redefine the alert() function before you create the chart. 

alert = function (str)
{
    console.log(str);
}
[No canvas support]

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: 
<canvas id="cvs" width="600" height="250">
    [No canvas support]
</canvas>
This is the code that generates the chart: