Inside Macintosh: AppleScript Language Guide / Part 2 - AppleScript Language Reference

Chapter 6 - Expressions / Script Properties

Defining Script Properties

The syntax for defining a script property is

( prop | property ) propertyLabel : initialValue  

where

propertyLabel is an identifier. The rules for specifying identifiers are listed in "Identifiers" on page 26.

initialValue is the value that is assigned to the property when you first run the script that contains the property or when you save it or check its syntax.

After you define a script property, you change its value the same way you change variable values: with the Set or Copy command. You can get a script property value using the Get command or by using it in an expression.