AJAX Form Pro

The forms work with jQuery by default, but can be ported to MooTools and Prototype without much hassle.

This script is also available as a WordPress plugin.

Features:

• HTML Code Separated from the PHP Code
• Real-Time Validator
• Easily send mail to multiple recipients/webmasters
• Send Mail with Attachments
• Redirect to Thank You page after Successful Submission
• Fully (CSS & HTML) Customizable
• Turns into a simple PHP Contact Form if JavaScript is disabled
• Tableless
• Powerful CAPTCHA
• Create unlimited AJAX Forms in the same page/multiple pages
• Auto Responder
• Lightbox integration
• Modal Form with Sliding Transition (Left & Top)
• Send mails using either mail() function or through SMTP
• Documentation
• Source Code Available

Requirements:

• PHP 4 or higher
• GD Library enabled if using CAPTCHA fields