this.x = 9;
var test = {
  x: 81,
  getX: function() {
    return this.x;
  }
};
console.log(test.getX()); // 81


var retrieveX = test.getX;
console.log(retrieveX()); // 9
/*
  var retrieveX = function() {
    return this.x;
  };
*/


var hello = {
  x: 100,
  getX: function() {
    return this.x;
  }
}
var boundGetX = retrieveX.bind(hello);
console.log(boundGetX()); // 100
/*
  var retrieveX = hello = {
    x: 100,
    getX: function() {
      return this.x;
    }
  };
*/