Livecode Wiki

In LiveCode, a handler is similar to a subroutine in other programming languages. It gets its name because it “handles” a task. A handler has a starting statement and a ending statement. But the real work of the handler is done by the list of statements between the starting and ending. For example:

on MouseUp
  put "Hello world!"
end MouseUp

There are several different types of Handlers:

Also see: Variables, Messages, Properties, Custom properties