For web developer

Securimage is an free PHP captcha script used for protecting web forms from spam and abuse.

It can be easily installed and very well documented.

Different than the famous reCAPTCHA, which is web-based, Securimage is a downloadable solution that requires PHP and GD library to work.

Some feature of this captcha solution:

Show an image in just 3 lines of code
Validate submitted entries in less than 6 lines of code
Customizable code length
Choose the character set
TTF font support
Use custom GD fonts when TTF is not available
Easily add background images
Multi colored, angled, and transparent text options
Arched lines through text
Generates audible CAPTCHA files in wav format
Use a word list for creating CAPTCHA codes

You can find a demo of the captcha here.

Requirements: PHP 4.3+, GD Library

For the projects that you don’t already have form controls, wForms is an open source unobtrusive JavaScript form controls library that you’ll find very useful.

It includes input validation, tooltips, field synchronization controls and more.

How to use wForms?

It is pretty easy. After inserting the javaScript library to your pages you can control the field attributes with classes like:

<input type="text" … class="required"/>

inserts the a required field control for this input.

Paging with navigation is also another nice control which makes multi-step forms easy to handle.

Requirements: No Requirements
Compatibility: All Major Browsers

LightForm is an AJAX – PHP Contact Form is a simple but handy script for creating charming & secure contact forms.

It uses FormCheck2 for validation and NiceForms for the styling of the form.

LightForm has the "question asking"  feature for eliminating spams & it provides the user IP, referrer and browser agent in the message to provide more details about the visitor.

Compatibility: All Major Browsers

Control Suite is a set of 6 high quality widgets and controls built with the Prototype JavaScript framework.

Each script is well tested, highly extensible and unobstrusive.

Suite has these widgets and controls:

Tab
Modal
TextArea
Select Multiple
Rating
Progress Bar

Different approach to star rating:

Suite is very well documented. You can easily reach the details of the APIs and this makes the product much more usable.

Requirements: Prototype JavaScript Library
Compatibility: All Major Browsers

Virtual keyboard interfaces are generally used in websites where the highest level of security is a must like online banking applications.

Virtual keyboards help us to prevent any keylogging activies and/or provide users a special keyboard which they don’t already have (like a keyboard of another language).

This virtual keyboard very easy to use and already supports many languages.

How to use virtual keyboard?

You simply include the keyboard.js file and create a text element with the class = keyboardInput. That’s all.

Requirements: No Requirements
Compatibility: All Major B>rowsers

mooRainbow is an easy to integrate JavaScript color picker built with mootools.

This color picker can be attached to any element in the DOM. A click event would automatically be attached to that element and simply clicking on it you will be able to show or hide mooRainbow.

This mootools powered JavaScript color picker:

is fully customizable via CSS file.
keeps clean your DOM and generates valid XHTML and CSS.
provides you, as return, an object containing RGB, HSB and HEX of choosen color.
works on Firefox/Safari/Opera/IE.

Requirements: mootools v.1.11+
Compatibility: All Major Browsers

Input masks are handy for better form handling and creating more user-friendly forms.

Masks for different input types can be created easily with the tools below.

iMask

iMask is an open source (free) javascript tool for creating input and textarea masking. It is built on Mootools, supports keyboard control and dynamic charset definition.

Masked Input Plugin for jQuery

This is a masked input plugin for the jQuery javascript library. It allows a user to more easily enter fixed width input where you would like them to enter the data in a certain format (dates,phone numbers, etc).

Password Field Image Mask

A nice JavaScript input mask which helps displaying the password field characters as images.

dFilter

A tiny JavaScript for input masking.

JavaScript Mask API

A simple yet nice input mask.

JavaScripTools

JavaScripTools is a set of JavaScript components, functions and classes which also includes a powerful input mask library.

Typecast – The Input Field Library

Typecast is an input field augmentation library. When complete it will add autocomplete, suggest and realtime character masking ability to the standard HTML input field.

SearchField is a lightweight and unobtrusive script that adds styling and static auto-suggest behaviour to your search form fields.

Auto-suggest data comes from a static data source, a JavaScript file, no data connections are necessary, updating the JavaScript with the common phrases is enough.

To use SearchField, all you need is linking to the CSS and JavaScript files, that’s all.

inWriter is a small JavaScript class that makes inline editing of textfields possible with a very simple coding.

How to use?

Just execute the inwriter_init function, passing the ID off the field you want to edit and the name of the function to call after the editing has been completed.
The called function receives two parameters:

ID of the tag
new value

That’s all!

Compatibility: All Major Browsers

ColorPicker is an advanced and highly customizable JavaScript color picker that doesn't rely on any JS frameworks.

It can display the entire color palette (~16.78 mil. colors) in 6 different color modes.

The picker 4 different sizes; from simple to the most advanced one and has 9 color memories (just like the ones in image editing apps.).

The script is totally skinnable with CSS and it is draggable (can be disabled) for an easier use.

ColorPicker can calculate the web smart/web safe versions of a selected color and much more.

Requirements: No Requirements
Compatibility: All Major Browsers