A demo of the dotted or dashed background grid (limited browser support)

This uses the relatively recent addition to canvas from the canvas v5 specification - native dotted and dashed lines. In somewhat limited testing it worked in Chrome, Firefox and Internet Explorer 11.

backgroundGridDashed: true,
backgroundGridDotted: true
[No canvas support] [No canvas support]

This goes in the documents header:
<script src="RGraph.common.core.js"></script>
<script src="RGraph.gantt.js"></script>
Put this where you want the chart to show up:
<canvas id="cvs1" width="600" height="250">[No canvas support]</canvas>
<canvas id="cvs2" width="600" height="250">[No canvas support]</canvas>
This is the code that generates the chart:
<script>
    new RGraph.Gantt({
        id: 'cvs1',
        data: [
            {start: 0, duration: 5, complete: 50, label: 'Richard'},
            {start: 3, duration: 2, complete: 25, label: 'John'},
            {start: 3, duration: 2, complete: 10, label: 'Fred'}
        ],
        options: {
            xaxisLabels: ['Monday','Tuesday','Wednesday','Thursday','Friday'],
            xaxisScaleMax: 5,
            title: 'A dashed background grid',
            titleY: 25,
            backgroundGridDashed: true,
            marginRight: 45
        }
    }).draw();



    new RGraph.Gantt({
        id: 'cvs2',
        data: [
            {start: 0, duration: 5, complete: 50, label: 'Richard'},
            {start: 3, duration: 2, complete: 25, label: 'John'},
            {start: 3, duration: 2, complete: 10, label: 'Fred'}
        ],
        options: {
            xaxisLabels: ['Monday','Tuesday','Wednesday','Thursday','Friday'],
            xaxisScaleMax: 5,
            title: 'A dotted background grid',
            titleY: 25,
            backgroundGridDotted: true,
            marginRight: 45
        }
    }).draw();
</script>