Native Form Elements is a web app that lists all of the native form elements for the visitor’s current browser.

This application is useful to see how form elements behave in each browser. It’s useful to know how they blend into your design and which ones of them function on, e.g., an outdated version.

So, if you want to compare these differences between browsers, simply open the app in another one.

Validatr is an HTML5 form validator that works across a number of browsers.

Validatr relies on modern HTML5 input attributes to perform form validation. If it’s not supported, Validator will use Modernizr to perform the validation.

It’s super easy to use and has a number of powerful validation methods; this plugin is also heavily customizable.

Parsley.js is a library for validating client-side forms without any extra code.

Parsley sports a number of “type constraints” that make using this library fairly easy. The library focuses on providing a good user experience and, along with a number of default methods, features ways to override them.

Happy.js is a jQuery/Zepto form validation plugin that’s easy to use and implement.

Happy.js only features one form of validation by itself–namely, you can name a field ‘required’, and that’s it.

Luckily, though, tests can be passed to the plugin with ease and writing validation tests is a good exercise for your programming brain at the very least.

jQuery.my is a plugin that binds HTML with JS objects in real-time.

The plugin is useful for form validation and formatting, as well as complex data mapping.

As can be seen from the picture, jQuery.my supports jQuery UI; the lightweight plugin also supports numerous validation methods and conditional formatting.

jQuery.my is definitely recommended to anyone having trouble with form validation — it’s easy to get into, as it accepts regexp patterns, and powerful once you get a hang of it.

InputNotes is a small jQuery plugin for adding notes below input fields, based on regex patterns you provide.

InputNotes provides a way of implementing input text checking; the plugin can also execute callbacks, but of course you need to add input checking on server-side, too.

Overall InputNotes is a nice plugin for unobtrusively telling the user what behavior is expected from him when filling forms and other data.