JavaScript Form Validation, the Aspect-Oriented Way : Page 2

More Form Validation

Requiring certain fields to have a value is a good starting point, but often applications demand more sophisticated validation capabilities. QForms rises to this challenge.

Out-of-the-Box Validation Methods

A variety of field validation methods come pre-built with qForms. To use these methods, simply reference the form and the form field name, and then call the method:

myForm.fieldName.validateXXX()

The following are just some of the validation methods qForms supports:

validateAlpha()
validateAlphaNumeric()
validateCreditCard()
validateDate()
validateEmail()
validateInteger()
validateLength()
validatePassword()
validatePhoneNumber()
validateSSN()
validateState()
validateZipCode()

Each of these methods also has an isXXX() version that returns a Boolean value and can be used in customized validation routines (described below).

Additional validation methods include the following:

• createDependencyTo() – The designated field is required only if the source field is selected/completed.
• isNotNull()/isNotEmpty() – Evaluate null and empty cases regardless of the field type (text, check/radio group, selection, and etc.).
• validateAtLeastOne() – List n number of fields, requiring at least one of them to be selected/completed.

Custom Validation Routines

Beyond its stock validation routines, qForms offers a rather extensive capability to define custom validation routines. This extensibility centers around two key methods:

• validateExp() – evaluates the supplied Boolean expression to determine a field's validity, such as verifying that a particular field is equal to a certain value, or ensuring that a field contains a certain number of characters
• _addValidator() – facilitates the creation of a fully customizable JS function that serves as a new Validator (complete with validateXXX() and isXXX() methods)

Time-Saving Form Validation

The qForms API is a simple, flexible JavaScript library that eases the development and maintenance of client-side JavaScript. In particular, qForms is an effective library for defining HTML form validation in a very lightweight, aspect-oriented manner. The next time that you are faced with the need for client-side validation of a Web form, give qForms a try. It just might reduce your development time and testing cycles, while leaving your forms clean and crisp.

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