11.14. Validating Form Input
You want to validate user input before allowing a form to be submitted for processing.
Write a custom
validate( ) method for
Form class that
checks each form element.
ActionScript does not provide a native means by which to validate
form input. However, you can add a small amount of code to the custom
Form class, with which you can then quickly add
validation code to any form. You should add two methods to the custom
Form class and add one line of code to the
setValidator( ), should
be used to set the validators for any
elements requiring validation. The method should take two parameters:
the name of the form element as a string and the validator.
The validator can have one of three types of values:
If the Boolean
trueis specified, the element must contain a value. Use this for mandatory form elements.
If the string “email” is specified, the element’s value must be in the format of a valid email address.
- Regular expression
If a regular expression is specified, it defines the pattern that the element value must match.
setValidator( ) method adds new elements to
an associative array in which the key is the element name and the
value is the validator. You should, therefore, initialize the
associative array in the constructor method.
validate( ) method performs the validation
based on the validators that have been specified using
setValidator( ). The
) method should ...