A Script is a type of Lua code container that will run its contents on the server. By default, Scripts have print("Hello, world") as their contents. The instant that the following conditions are met, a Script’s Lua code is run in a new thread:
Disabled property is false
The Script object is a descendant of the Workspace or
The Script will continue to run until the above conditions are not met, it terminates or it raises an error (unless that error is raised by a function connected to some event that is firing). Additionally, the thread will be stopped if the Script or one of its ancestors is destroyed. A script will continue to run even if the Parent property is set to nil (and the Script is not destroyed).
It has access to server-side objects, properties and events. For example, Scripts can award badges to players using BadgeService, while a LocalScript on the client cannot. Actions taken by LocalScripts that are not replicated (due to FilteringEnabled) will not be visible to Scripts.