FunctionScope.js

var a = 10; 
//Global Scope
function function1() {
  var a = 20; // function1 Scope
  console.log(a); //imprime 20
  
  function function2() {
    var a = 30; //function2 scope
    console.log(a); //imprime 30
  }
  
  function2(); 
  console.log(a); // imprime 20
  
}

console.log(a); //imprime 10