jQuery Real Person

This plugin enhances an input field to help reduce automated form submission. * Server-side scripts for PHP, Java, C#, ColdFusion, Rails, Python.

jQuery Form Validate

jQuery Form Validate is a simple form validation plugin that allows you to easily validate your forms by applying various HTML data attributes.

jQuery DOM Polling Plugin

Allows you add custom events that can be precisely configured to track changes on DOM nodes (from simple form text updates to tracking anything like CSS position). These events support jQuery Event API (including event delegation!). Plays nicely with resources, monitors DOM updates, clears caches whenever necessary

validator

The Validator is cross-browser and will give you the power to use future-proof input types such as ‘tel’, ’email’, ‘number’, ‘date’, and ‘url’. I can sum this as a ‘template’ for creating web forms. It uses the power of custom ‘data’ to achieve high flexibility

A form in slider form

jFormslider is a jquey plugin which you can implement a form in form of a slider

Validate.js

A barebones jQuery validation plugin.

TieJS

TieJS makes it easy to create forms via JSON and bind objects to its form fields. Furthermore it has HTML5 validation functionalities.

JavaScript Utilities

A suite of utilities for JavaScript and jQuery, which includes tools for validating, text formatting, and other features.

jQuery Max Length

This plugin applies a maximum length to a textarea. * Always truncate or only warn when limit reached. * Customise the user feedback.