Hypertext preprocessor $($PHP$)$ allows the web page that the user sees to communicate with the server. $3$ functions of PHP include:

Allows users to store and manipulate numerical data and create charts.

Handle forms. For example, it can gather data from files, save data to a file, send data by email to the website owner or return data to the user.

Perform system functions such as creating, opening, reading, writing, and closing files.

Allows the website owner to add, delete, and modify elements within a database.