Building a calories counter. Based on the freecodecamp project.
reference source : https://www.freecodecamp.org/learn/javascript-algorithms-and-data-structures-v8/
Sometimes when you're coding a web application, you'll need to be able to accept input from a user. In this calorie counter project, you'll learn how to validate user input, perform calculations based on that input, and dynamically update your interface to display the results.