59.js

if (typeof Function.prototype.method !== "function") {
  Function.prototype.method = function (name, implementation) {
    this.prototype[name] = implementation;
    return this;
  };
}

var Person = function (name){
  this.name = name;
}.
  method('getName', function(){
    return this.name;
  }).
  method('setName', function(name){
    this.name = name;
    return this;
  });

var a = new Person('Adam');
document.writeln(a.getName());
document.writeln(a.setName('Eve').getName());