This repository contains one web page with a web form to check if a year is a leap year or not. If the year is a leap year, we get the answer "Yes, the year is a leap year!", otherwise "No, the year is not a leap year!" So, with a PHP function that uses the remainder of dividing by 4, it is checked whether the entered year is a leap year or not.
To check how it looks, click on the preview and then on the green run button.