This uses the newer addition to canvas from the canvas v5 specification - native dotted and dashed lines. As browsers add support you will be able to use the option in those too but initially it's only supported in Chrome.
obj.Set('background.grid.dashed', true);
obj.Set('background.grid.dotted', true);
This goes in the documents header:
<script src="RGraph.common.core.js"></script> <script src="RGraph.waterfall.js"></script>Put this where you want the chart to show up:
<canvas id="cvs1" width="600" height="250">
<canvas id="cvs2" width="600" height="250">
[No canvas support]
</canvas>
This is the code that generates the chart:
<script>
new RGraph.Waterfall({
id: 'cvs1',
data: [4,8,6,5,-5,-6,6,-5,-4,-3,2,1],
options: {
gutterTop: 35,
backgroundGridDashed: true,
backgroundGridAutofitNumvlines: 13,
labels: [
'Mal', 'Barry',
'Gary', 'Neil',
'Kim', 'Pete',
'Lou', 'Fred',
'Jobe', 'Fred',
'Harry', 'Jake',
'Total'
],
title: 'A dashed background grid',
textSize: 12,
strokestyle: 'rgba(0,0,0,0)'
}
}).draw()
new RGraph.Waterfall({
id: 'cvs2',
data: [4,8,6,5,-5,-6,6,-5,-4,-3,2,1],
options: {
gutterTop: 35,
labels: [
'Mal', 'Barry',
'Gary', 'Neil',
'Kim', 'Pete',
'Lou', 'Fred',
'Jobe', 'Lucy',
'Kevin', 'Nevil'
],
backgroundGridDotted: true,
title: 'A dotted background grid',
strokestyle: 'rgba(0,0,0,0)'
}
}).draw();
</script>