A custom action can call functions that are written in VBScript or JScript. Windows Installer does not provide the script engine. Authors wishing to make use of a scripting language during installation must therefore ensure that the appropriate scripting engine is available.

The installer does not support JScript version 1.0.

A 64-bit custom action based on scripts must be explicitly marked as a 64-bit custom action by adding the msidbCustomActionType64BitScript bit to the custom actions numeric type in the Type column of the CustomAction table. For information see 64-Bit Custom Actions.

The following basic custom action types call functions written in script.

Note  The installer runs script custom actions directly and does not use the Windows Script Host. The WScript object cannot be used inside a script custom action because this object is provided by the Windows Script Host. Objects in the Windows Script Host object model can only be used in custom actions if Windows Script Host is installed on the computer by creating new instances of the object, with a call to CreateObject, and providing the ProgId of the object (for example "WScript.Shell"). Depending on the type of script custom action, access to some objects and methods of the Windows Script Host object model may be denied for security reasons.

For more information, see Summary List of All Custom Action Types for a summary of all types of custom actions and how they are encoded into the CustomAction table.

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Build date: 8/13/2009