Question

Does anyone know why the last alert in the code below complains that a is undefined. Shouldn’t a is 11 because it’s initialized in four() without using the var keyword? Thanks.

function three() {
  var a = 12
  function four() {
    a = 11
    function five() {
      alert(a)
    }
    return five
  }
  return four
}
three()()()
alert(a)

Answer 1

No, because a has been declared with “var”, the assignment to a in four() refers to that declared variable, and the scope of a is limited to three().