Why is my Javascript increment operator (++) not working properly in my addOne function [duplicate]

Answer 1

That is not the correct use of ++, but also a lot of people would not recommend using ++ at all. ++ mutates the variable and returns its previous value. Try the example below.

var two = 2;
var three = two += 1;
alert(two + ' ' + three);

two = 2;
three = two++;
alert(two + ' ' +  three);

two = 2;
three = two + 1;
alert(two + ' ' +  three);