Zend Framework comes with a standard set of validation classes, which are ready for you to use. Returns TRUE if and only if $value contains only alphabetic and digit characters. This validator includes an option to also consider white space characters as valid. The alphabetic characters mean characters that makes up words in each language. However, the English alphabet is treated as the alphabetic characters in following languages: Chinese, Japanese, Korean. The language is specified by Zend_Locale. Returns TRUE if and only if $value contains only alphabetic characters. This validator includes an option to also consider white space characters as valid. The Ccnum validator has been deprecated in favor of the CreditCard validator. For security reasons you should use CreditCard instead of Ccnum. Returns TRUE if $value is a valid date of the format 'YYYY-MM-DD'. If the optional locale option is set then the date will be validated according to the set locale. And if the optional format option is set this format is used for the validation. for details about the optional parameters see Zend_Date::isDate(). Returns TRUE if and only if $value only contains digit characters. Returns TRUE if and only if $value is a floating-point value. Since Zend Framework 1.8 this validator takes into account the actual locale from browser, environment or application wide set locale. You can of course use the get/setLocale accessors to change the used locale or give it while creating a instance of this validator.