A script handler you can implement to override standard MoneyWorks behaviour.
Automatically called: Whenever the contents of a field changes. This includes typing a a character into an edit field; clicking a checkbox; changing a popup menu.
Use for: Reacting immediately to a control change or as a chance to call AutoFill on a code field
Specific Naming: You can and should implement an Itemhit handler that is specific to the particular window ID and itemID of interest. e.g. Itemhit:<WindowId>:ItemID:TransactionType (the last of these applies only when the WindowID is F_TRANS)