A Line chart with customised Y labels

In order to show significantly customised labels you can either draw the axes yourself using the draw event or, as is done in this case, you can use the drawing API Y axis object. The axes are offset slightly by using the margins so the labels appear to be sitting on top of the grid lines. The axes of the Line chart are turned off and the color of the axis line is transparent so that just the text labels are visible.

<script src="RGraph.drawing.yaxis.js"></script>
<script src="RGraph.common.core.js"></script>
<script src="RGraph.common.tooltips.js"></script>
<script src="RGraph.common.dynamic.js"></script>
<script src="RGraph.line.js"></script>

<div style="float: right; border: 1px solid gray">
    <canvas width="600" height="250" style="float: right" >[No canvas support]</canvas>
</div>