Description: Superglobals in PHP are built-in global arrays that are always accessible, regardless of the scope in which they are found. This means that, unlike normal variables that have limited scope, superglobals can be used anywhere in the script, making them very useful tools for data management. PHP includes several superglobals, among which the most notable are: $_GET, $_POST, $_SESSION, $_COOKIE, $_FILES, $_SERVER, and $_REQUEST. Each of these superglobals has a specific purpose and allows access to different types of information. For example, $_GET is used to access data sent via the URL, while $_POST is used for data sent through forms. The characteristic of being global facilitates interaction between different parts of a web application, allowing for more efficient information handling. Additionally, their use is fundamental in the development of dynamic web applications, where user interaction and session management are essential for site functionality. In summary, superglobals are an integral part of PHP that simplifies data access and improves code structure, enabling developers to create more robust and efficient applications.
History: Superglobals were introduced in PHP 4, which was released in 2000. Since then, they have evolved and become an essential part of the language, especially with the arrival of PHP 5 and later versions, where session management and data handling security were improved. Over the years, the PHP community has worked to standardize and optimize the use of these superglobals, ensuring they are reliable tools for developers.
Uses: Superglobals are primarily used to access form data, manage user sessions, handle cookies, and obtain server information. They are fundamental in web application development as they allow efficient interaction between the client and the server. For example, $_SESSION is used to store information about the user throughout their visit, while $_COOKIE allows data to be stored in the client’s browser.
Examples: A practical example of using superglobals is handling a login form. When a user submits their username and password through a form, this data can be accessed using the $_POST superglobal. Subsequently, user information can be stored in $_SESSION to keep them authenticated during their browsing. Another example is using $_GET to retrieve parameters from the URL, such as in a search system where search terms are passed through the URL.
