"Inheritance" doesn't really exist in JS. We use that word because we don't have a better substitute, but what Javascript has is simply code sharing. You can share code between multiple objects. This is accomplished by using prototypes. An object has access to all the code defined on its prototype (and its prototype's prototype, and...). If two objects have the same prototype they will have access to the same methods.
Now, unfortunately, the native Javascript way of saying "please set the prototype of this object to X" is not very intuitive. So again we reused an existing word -- "class" -- and defined it to be "a thing that creates an object and sets its prototype to be what I want".
However, actually creating these class things is painful and verbose in vanilla Javascript, so everyone uses a library to do it for them. I use classdef [1] because I wrote it and it works just the way I want it to, but seriously there are a million options out there. Go find one and use it.