Declaring variables. Nowadays JavaScript has three different keywords to declare a variable ... Simply add an if statement inside a function. So, let’s see an example: Lexical scope.

Functions are self-contained routines that can be “called” elsewhere within your JavaScript code. Along with loops and conditionals, functions are an essential means of organizing software.

When you're declaring variables in a script outside of a function, this distinction is pretty much irrelevant. When you're declaring a variable inside a function and do not use var this creates a ...