What is the difference between a prototype and a class in JavaScript?

In JavaScript, there are several ways to define objects using the "class" or the "Function" syntax or using prototypes:

• What is the difference between modifying a property or method on a prototype and modifying a property or method on a class in JavaScript?
• What is the difference between defining properties and methods on a prototype versus defining them in the constructor function in JavaScript?
• What are the differences between using the function keyword to create a class in JavaScript, versus using the prototype property to define properties and methods on an object, versus using the class keyword with the extends and implements keywords to create a class?