ArcGIS Server can expose geoprocessing models as services, which your ArcGIS API for JavaScript applications can access. These models execute on the ArcGIS Server due to their computationally intensive nature and the fact that they need ArcGIS components not available in the API to do their work. You submit these requests to the server via your application together with the required parameters, and the results are returned when the task completes.
Geoprocessing tasks can execute either synchronously or asynchronously and are configured to run as such by an ArcGIS Server administrator. As an application programmer, it is important for you to understand what type of geoprocessing service you are accessing since the method you must call to execute the task depends upon this information. You also need to pay careful attention to the parameters required by the service, and this information is available in the services directory. In the next chapter, you will learn how to use the Geometry...