javascript Demo

var vm=(function(){
  var name="jasper";
  var changename=function(v){
   name=v;
  };
  
  return {
    name:name,
    changename:changename
  };
})();

vm.changename("sean");
alert(vm.name);

var vm=(function(){
  var person={name:"jasper"};
  var changename=function(v){
   person.name=v;
  };
  
  return {
    person:person,
    changename:changename
  };
})();

vm.changename("sean");
alert(vm.person.name);

 var vm = (function () {
            var person = { name: "jasper" };
            var changename = function (v) {
                //person.name = v;
                person = { };
            };

            return {
                person: person,
                changename: changename
            };
        })();

        vm.changename("sean");
        alert(vm.person.name);