Documentation I forgot to add to the last commit.

doc/json-config-parameters.md

@@ -214,6 +214,12 @@ If `createTooltipFunc` is specified, this function is used to create the hot
 spot tooltip DOM instead of the default function. The contents of
 `createTooltipArgs` are passed to the function as arguments.
 
+#### `clickHandlerFunc` (function) and `clickHandlerArgs` (object)
+
+If `clickHandlerFunc` is specified, this function is added as an event handler
+for the hot spot's `click` event. The event object and the contents of
+`clickHandlerArgs` are passed to the function as arguments.
+
 ### `hotSpotDebug` (boolean)
 
 When `true`, the mouse pointer's pitch and yaw are logged to the console when