User Guide

626 Chapter 14: Properties
alertHook
Usage
-- Lingo syntax
_player.alertHook
// JavaScript syntax
_player.alertHook;
Description
Player property; specifies a parent script that contains the alertHook handler. Read/write.
Use
alertHook to control the display of alerts about file errors or script errors. When an error
occurs and a parent script is assigned to
alertHook, Director runs the alertHook handler in the
parent script.
Although it is possible to place
alertHook handlers in movie scripts, it is strongly recommended
that you place an
alertHook handler in a behavior or parent script to avoid unintentionally
calling the handler from a wide variety of locations and creating confusion about where the
error occurred.
Because the
alertHook handler runs when an error occurs, avoid using the alertHook handler
for script that isn't involved in handling an error. For example, the
alertHook handler is a bad
location for a
go() statement.
The
alertHook handler is passed an instance argument, two string arguments that describe the
error, and an optional argument specifying an additional event that invokes the handler.
The fourth argument can have 1 of these 4 values:
• #alert—causes the handler to be triggered by the alert() method.
• #movie—causes the handler to be triggered by a file not found error while performing a go()
command.
• #script—causes the handler to be triggered by a script error.
• #safeplayer—causes the handler to be triggered by a check of the safePlayer property.
Depending on the script within it, the
alertHook handler can ignore the error or report it in
another way.
Example
The following statement specifies that the parent script Alert is the script that determines whether
to display alerts when an error occurs. If an error occurs, the script assigns the error and message
strings to the field cast member Output and returns the value 1.
-- Lingo syntax
on prepareMovie
_player.alertHook = script("Alert")
end
-- "Alert" script
on alertHook me, err, msg
member("Output").text = err && msg
return 1
end