Here is an interesting example for Classes in JS. Classes in JS don’t have a class keyword. ```JavaScript function Range(from, to) { this. from = from; this. to = to; } Range. prototype = { includes: function (x) { return this. from <=x && x <= this. to; }, foreach: function (f) { for(var x= Math. ceil(this. from); x < this. to; x++)f(x); }, toString: function () { return ’(‘+this. from+’.’+this. to+’)’; } }; var r = new Range(4,20); r. includes(5); r. foreach(console. log); console. log(r);