VDaemon is a PHP library that grants an easy-to-use but powerful way to check user input for errors, and, if necessary, display messages to the user.
VDaemon performs server-side validation using PHP and client-side validation using JavaScript.
VDaemon can perform wide range of validation tasks. It includes mandatory fields validation, validation for properly formatted value (currently supported types are e-mail address, zip codes for US, Canada and UK, US phone number, IP address, date and time in various formats, integer and floaf numbers, currency), comparing entered value to the predefined value or to another form element value, validating against regular expression pattern and more.
VDaemon allows combining validation rules into logical expressions of any complexity. It gives possibility to create a conditional validation.
VDaemon allows to highlight invalid form elements and/or corresponding labels by assigning them an alternative CSS styles. It automatically sets focus to the first invalid form element.
VDaemon can collect and display all error messages in one place on a page.
VDaemon leaves the behaviour of HTML forms unchanged. This allows easy incorporation of VDaemon validation into existing web sites.
VDaemon produces XHTML compliant code.
And more ...
Requirements:
PHP version 4.2.0 or later is required for server-side validation. | 
