Yesterday I was looking to check if a point was inside a polygon and found this great script: https://github.com/tparkin/Google-Maps-Point-in-Polygon

But today at work I was told that our client needs to check if one polygon is inside another polygon. I am wondering if is there a formula where I can take, let's say, two coordinates (instead of one to check a point), and from those two coordinates generate a rectangle and check if that rectangle is inside a polygon.

I don't know if I'm asking a stupid question (a teacher in highschool used to say there are no stupid questions, there is only fools who don't ask), but if you don't understand me totally but just a bit, I'd be grateful if you just tell me where to start.