Form validation can be a nightmare for some of us but it is a good practise to include both client-side and server-side validation. You might think it's a redundant effort, but come and think about it from the end user's point of view, client-side validation can save time and save bandwidth by allowing user correct errors on the spot without have to submit it back to the server.
- Zebra Form This is something different. Zebra_Form is a free PHP library, handles this process very well and enables us to create secure and chic forms with a few lines of PHP code. However, it integrates with jQuery in the frontend to display alerts and errors,. It's worthwhile to be mentioned here.
- jFormer jFormer, a form framework built on top of jQuery brings a complete, easy-to-use and solid solution to handling them. It enables us to build forms which are validated on client-side and server-side (PHP solution is included) with Ajax requests where users are notified in a very chic way with tooltips and CSS-styling on every level.
- jQuery.validVal jQuery.validVal is plugin for the popular JS framework which aims to simplify form validation. It can be used for validating any kind of HTML form (including Ajaxed ones) and works by defining the rules within class names.
- Validity Validity is a powerful and flexible jQuery form validation for making sure -on the client-side- that form values are just as expected. It is lightweight (9kb) and can perform simple to complex, dynamic and conditional validations. The plugin also gives full control over how validation messages will appear which makes it possible to match the look and feel of your site.
- Ketchup Ketchup is an easy-to-customize (in means of appearance & functionality) jQuery plugin for validating user inputs on the client-side.
- Form Validator jQuery form validator is a versatile solution that works with every form. It displays floating error tooltips whenever the validation fails.
- VanadiumJS VanadiumJS is an intuitive-yet-powerful jQuery plugin for easy client-side validation.