PHP is a scripting language. It was designed for producing dynamic web pages. Now it can include a command line interface capability and can be used in standalone graphical applications. It is similar to other server-side scripts that provide dynamic content from a web server to a client, such as Microsoft's Active Server Pages, Sun Microsystems' JavaServer Pages, and mod_perl. PHP executes hundreds of base functions and thousands more via extensions.
The PHP Group produces the main implementation of PHP which serves as the de facto standard for PHP, because there is no formal specification now. PHP Group provides the complete source code for users to build, customize and extend for their own use. It is considered a free software released under the PHP License. But it is incompatible with the GNU General Public License (GPL) as there are restrictions on the usage of the term PHP.
PHP is a widely-used general-purpose scripting language that can be embedded into HTML. It generally runs on a web server and creates web pages taking PHP code. It is also used for command-line scripting and client-side GUI applications. It works on most web servers, operating systems and platforms free of charge. PHP can be used with many relational database management systems. Now it functions on more than 20 million websites and 1 million web servers.
PHP can be compared to a filter as it takes input from a file or stream containing text and/or PHP instructions and outputs another data; HTML is the most common output. It can automatically identify the language of the user.
One who has ever created any HTML page or started dynamic web programming, has already met with forms. Forms are special components which allow the site visitors to add information on the HTML page.
A PHP form on a web page allows a user to enter data that is sent to a server for processing. For instance, almost each company web site contains a contact form, so that visitors can send a message to the site owner. Such a contact form usually contains several fields - for the visitor’s name, for the email address and one for the main message. PHP forms resemble paper forms because internet users fill out the forms using checkboxes, radio buttons, or text fields. For example, the forms can be used to enter shipping or credit card data to order a product or can be used to retrieve data.
When dealing with HTML forms and PHP it is necessary to remember that any form element in HTML page will automatically be available to the PHP scripts.
Source: http://phpforms.net/
