This is a Scatter chart but as well as X and Y points it also has a Z point which makes the chart into a Bubble chart. The Scatter chart X axis labels aren't tied to specific points - they're just spread evenly across the X axis.
This goes in the documents header:<script src="RGraph.svg.common.core.js"></script> <script src="RGraph.svg.scatter.js"></script>Put this where you want the chart to show up:
<div style="width: 650px; height: 350px; border: 1px solid #ddd" id="chart-container"></div>This is the code that generates the chart: