A skeleton Gauge chart

This goes in the documents header:

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

Put this where you want the chart to show up:

<canvas id="cvs" width="300" height="150">
    [No canvas support]
</canvas>

This is the code that generates the chart:

<script>
    window.onload = function ()
    {
        var gauge = new RGraph.Gauge({
            id: 'cvs',
            min: 0,
            max: 50,
            value: 46,
            options: {
                centery: 120,
                radius: 130,
                anglesStart: RGraph.PI,
                anglesEnd: RGraph.TWOPI,
                needleSize: 85,
                borderWidth: 0,
                shadow: false,
                needleType: 'line',
                colorsRanges: [[0,10,'red'], [10,20,'yellow'],[20,50,'#0f0']],
                borderInner: 'rgba(0,0,0,0)',
                borderOuter: 'rgba(0,0,0,0)',
                borderOutline: 'rgba(0,0,0,0)',
                centerpinColor: 'rgba(0,0,0,0)',
                centerpinRadius: 0,
                textAccessible: true
            }
        }).grow()
        
        gauge.canvas.onclick = function (e)
        {
            var value = gauge.getValue(e);
            
            if (typeof value === 'number') {
                gauge.value = value;
                gauge.grow();
            }
        }
    };
</script>