A circular and adjustable Meter chart

This goes in the documents header:

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

Put this where you want the chart to show up:

<canvas id="cvs" width="400" height="250">
    [No canvas support]
</canvas>

This is the code that generates the chart:

<script>
    window.onload = function ()
    {
        var meter = new RGraph.Meter({
            id: 'cvs',
            min: -100,
            max: 100,
            value: -25,
            options: {
                anglesStart: RGraph.PI - 0.5,
                anglesEnd: RGraph.TWOPI + 0.5,
                linewidthSegments: 15,
                textSize: 16,
                strokestyle: 'white',
                segmentRadiusStart: 95,
                needleRadius: 75,
                border: 0,
                tickmarksSmallNum: 0,
                tickmarksBigNum: 0,
                colorsRanges: [[-100,-70, 'red'],[-70,70, '#0f0'],[70,100, 'red']],
                centery: 155,
                radius: 125,
                adjustable: true
            }
        }).draw();

        meter.onbeforedraw = function (obj)
        {
          RGraph.clear(obj.canvas, 'white');
        }
    };
</script>