The Line chart can be adjusted by dragging the line(s) up and down. When you click on a line to adjust it (and hold the mousebutton down) you can then retrieve the relevant details of that point from the registry:
RGraph.Registry.Get('chart.adjusting.shape');
<script> window.onload = function (e) { var line = new RGraph.Line('cvs', [45,74,84,85,45,35,65,68,87,97,45,34,12], [15,14,12,16,18,19,14,12,74,84,95,65,35]); line.Set('chart.labels', ['Kev','Matt','Rich','Dave','Iggy','Polly','Fiona','Fred','Pete','Lou','Fred','Bob']); line.Set('chart.ylabels.inside', true); line.Set('chart.linewidth', 2); line.Set('chart.hmargin', 10); line.Set('chart.shadow', true); line.Set('chart.adjustable', true); line.Set('chart.title', 'An adjustable line chart'); line.Set('chart.outofbounds', true); line.Draw(); } </script>