This is an exercise found at The Odin Project (http://www.theodinproject.com/web-development-101/javascript-basics?ref=lnav) It solves the first three Euler Problems found at https://projecteuler.net/archives.
JavaScript was used to solve all three problems. Ruby was used in a second pass.
The first one asks to sum up all numbers that are multiples of 3 and 5 between 1 and 1000.
The second one asks to sum up only the even Fibonacci numbers from 1 to 4 million.
The third one asks to find the largest prime factor of a rather large number.