MACROMEDIA FLASH MX 2004 - ACTIONSCRIPT - Page 733

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Example
In this example, a function named checkEmail() checks whether the string that is passed to it is
a properly formatted e-mail address. If the string does not contain an @ symbol, the function
throws an error.
function checkEmail(email:String) {
if (email.indexOf("@") == -1) {
throw new Error("Invalid email address");
}
}
The following code then calls the checkEmail() function within a try code block, passing the
text in a text field (
email_txt) as a parameter. If the string parameter does not contain a valid e-
mail address, the error message is displayed in a text field (
error_txt).
try {
checkEmail("Joe Smith”);
} catch (e) {
error_txt.text = e.toString();
}
In this example, a subclass of the Error class is thrown. The checkEmail() function is modified
to throw an instance of that subclass. (For more information, see “Creating subclasses”
on page 162.)
// Define Error subclass InvalidEmailError
// In InvalidEmailError.as:
class InvalidEmailAddress extends Error {
var message = "Invalid email address.";
}
function checkEmail(email:String) {
if (email.indexOf("@") == -1) {
throw new InvalidEmailAddress();
}
}
See also
Error class, try..catch..finally