# Program Interaction

Event-Handler Routines |

Event-handler routines are routines that are executed in response to certain events. The resultant action can range from performing complex program code to simply closing down a panel.

This Help section explains how to access and manipulate controls in your code, as well as how to control behavioral aspects of the NOMADS interface.

## See Also

Accessing and Manipulating Controls
Dynamic Properties
Load on Demand
Background Loading
Manipulating and Controlling Groups