The LocalConnection class lets you develop SWF files that can send instructions to each other. LocalConnection objects can communicate only among SWF files that are running on the same client computer, but they can be running in different applications--for example, a SWF file running in a browser and a SWF file running in a projector.

For every LocalConnection communication, there is a sender SWF file and a listener SWF file. By default, Flash Player allows LocalConnection communication between SWF files in the same domain. For SWF files in different sandboxes, the listener must allow the sender permission by using the LocalConnection.allowDomain() method. The string you pass as an argument to the LocalConnection.allowDomain() method can contain any of the following: exact domain names, IP addresses, and the * wildcard.

A SWF file can use the domain property of the LocalConnection class to determine its domain.