how to know what function you get inside function javascript code example

Example 1: closure in javascript

function makeFunc() {
  var name = 'Mozilla';
  function displayName() {
    alert(name);
  }
  return displayName;
}

var myFunc = makeFunc();
myFunc();

Example 2: call local function javascript

function x() {
};

x.y = function() { alert('2');};

function z() {  x.y(); }