function FatherClass() {
  this.type = 'father';
}
FatherClass.prototype.getTyep = function() {
  console.log(this.type);
}
FatherClass.prototype.obj = {age: 35};
function ChildClass() {
  this.type = 'child';
}
ChildClass.prototype = FatherClass();
ChildClass.prototype.getType = function() {
  console.log(this.type);
}
var father = new FatherClass();
var child = new ChildClass();
father.getTyep();
child.getType();

function FatherClass(type) {
  this.type = type || 'father';
}
function ChildClass(type) {
  this.type = type || 'child';
}
ChildClass.prototype = FatherClass();
ChildClass.prototype.getType = function() {
  console.log(this.type);
}
var father = new FatherClass('fatClass');
var child = new ChildClass('chilClass');

var Parent = function(name){
  this.name = name || 'parent' ;
} ;
Parent.prototype.getName = function(){
  return this.name ;
} ;
Parent.prototype.obj = {a : 1} ;
var Child = function(name){
  Parent.apply(this,arguments) ;
} ;
Child.prototype = Parent.prototype ;
var parent = new Parent('myParent') ;
var child = new Child('myChild') ;
console.log(parent.getName()) ; //myParent
console.log(child.getName()) ; //myChild

var Parent = function(name){
  this.name = name || 'parent' ;
} ;
Parent.prototype.getName = function(){
  return this.name ;
} ;
Parent.prototype.obj = {a : 1} ;
var Child = function(name){
  Parent.apply(this,arguments) ;
} ;
var F = new Function(){} ;
F.prototype = Parent.prototype ;
Child.prototype = new F() ;
var parent = new Parent('myParent') ;
var child = new Child('myChild') ;
console.log(parent.getName()) ; //myParent
console.log(child.getName()) ; //myChild

var Parent = function(name){
  this.name = name || 'parent' ;
} ;
Parent.prototype.getName = function(){
  return this.name ;
} ;
Parent.prototype.obj = {a : 1} ;
var Child = function(name){
  Parent.apply(this,arguments) ;
} ;
var F = new Function(){} ;
F.prototype = Parent.prototype ;
Child.prototype = new F() ;
var parent = new Parent('myParent') ;
var child = new Child('myChild') ;
console.log(child.obj.a) ; //1
console.log(parent.obj.a) ; //1
child.obj.a = 2 ;
console.log(child.obj.a) ; //2
console.log(parent.obj.a) ; //2

var Parent = function(name){
  this.name = name || 'parent' ;
} ;
Parent.prototype.getName = function(){
  return this.name ;
} ;
Parent.prototype.obj = {a : 1} ;
var Child = function(name){
  Parent.apply(this,arguments) ;
} ;
var F = new Function(){} ;
F.prototype = Parent.prototype ;
Child.prototype = new F() ;
var parent = new Parent('myParent') ;
var child = new Child('myChild') ;
console.log(child.obj.a) ; //1
console.log(parent.obj.a) ; //1
child.obj.a = 2 ;
console.log(child.obj.a) ; //2
console.log(parent.obj.a) ; //2

var deepClone = function(source,target){
  source = source || {} ;
  target = target || {};
  var toStr = Object.prototype.toString ,
    arrStr = '[object array]' ;
  for(var i in source){
    if(source.hasOwnProperty(i)){
      var item = source[i] ;
      if(typeof item === 'object'){
        target[i] = (toStr.apply(item).toLowerCase() === arrStr) ? [] : {} ;
        deepClone(item,target[i]) ;
      }else{
        target[i] = item;
      }
    }
  }
  return target ;
} ;
var Parent = function(name){
  this.name = name || 'parent' ;
} ;
Parent.prototype.getName = function(){
  return this.name ;
} ;
Parent.prototype.obj = {a : '1'} ;
var Child = function(name){
  Parent.apply(this,arguments) ;
} ;
Child.prototype = deepClone(Parent.prototype) ;
var child = new Child('child') ;
var parent = new Parent('parent') ;
console.log(child.obj.a) ; //1
console.log(parent.obj.a) ; //1
child.obj.a = '2' ;
console.log(child.obj.a) ; //2
console.log(parent.obj.a) ; //1

var deepClone = function(source,target){
  source = source || {} ;
  target = target || {};
  var toStr = Object.prototype.toString ,
    arrStr = '[object array]' ;
  for(var i in source){
    if(source.hasOwnProperty(i)){
      var item = source[i] ;
      if(typeof item === 'object'){
        target[i] = (toStr.apply(item).toLowerCase() === arrStr) ? [] : {} ;
        deepClone(item,target[i]) ;
      }else{
        target[i] = item;
      }
    }
  }
  return target ;
} ;
var extend = function(Parent,Child){
  Child = Child || function(){} ;
  if(Parent === undefined)
    return Child ;
  //借用父类构造函数
  Child = function(){
    Parent.apply(this,argument) ;
  } ;
  //通过深拷贝继承父类原型
  Child.prototype = deepClone(Parent.prototype) ;
  //重置constructor属性
  Child.prototype.constructor = Child ;
} ;