Refreshing Chart Data Using <apex:actionSupport>

This markup attaches a chart component to its data source by setting the chart’s data attribute to the Visualforce expression {!pieData}. The expression calls the getPieData() controller method, which returns the data. The chart is wrapped in an <apex:outputPanel> with an id attribute of theChart.

An <apex:form> component is used to submit a new year back to the page’s controller when the chart needs to be updated. The <apex:selectList> tag displays the years available to chart, and a child <apex:actionSupport> tag submits the form whenever the menu changes. The id of the chart’s <apex:outputPanel>, theChart, is used in the <apex:actionSupport> reRender attribute to limit updating to the chart, instead of reloading the whole page. Finally, an <apex:actionStatus> component provides a status message while the chart is refreshing. It’s easy to replace the minimal text message with an animated graphic or text effect.