t002-2.js

// file scope

var a; // declaration of 'a' moved on top of the file and split from assignment

console.log(a); // so here 'a' is undefined, but declared,
                // so it does not throw an error
a = 1; // now 'a' is assigned to 1
console.log(a);

function f1() { // f1 scope
  var b; // 'b' moved here

  console.log(a);

  console.log(b);
  b = 1;
  console.log(b);

  // TODO: try uncomment
  // console.log(x);
}

function f2() { // f2 scope
  function x() { // functions declarations are also moved on top,
                 // that is why we have access to x() anywhere inside f2()
    console.log('x');
  }

  console.log(x());
  // function x() { ... } is moved to the top
  console.log(x());

  // TODO: try uncomment
  // console.log(b);
}

f1();
f2();