Use the ClientInstanceName property to specify a unique client-side identifier for a Web Chart control. The ClientInstanceName property's value can be used on the client side to programmatically access the client object rendered for the chart in client-side script. This property is particularly important in referencing the chart when it is contained within a naming container (for instance, within an ASPxPageControl's page or an ASPxPopupControl's window).
If the ClientInstanceName property is not specified, a chart's client identifier is generated automatically and equals the value of the chart's ID property. Note that in this case, client-side programmatic access to the chart by its ID is not allowed when the chart is contained within a naming container.