To set up a chart drilldown with chart response
When you click on a chart, the name of the chart section you clicked will be passed to the alpha field bound to the chart response property and control is then passed back to your RPG program. Your program can determine what section was clicked by evaluating the field and take whatever action is required, perhaps displaying a second chart or other relevant data.
To set up a client side event such as opening a specific browser window
Details on how to use these properties are available here: