js---OOP浅谈

对象化编程-------简单地去理解就是把javascript能涉及到的范围分成各种对象,对象下面再次划分对象。编程出发点多是对象,或者说基于对象。所说的对象既包含变量,网页,窗口等等
 
对象的含义
          对象可以是文字,表单等等。对象包含一下
属性-------对象的某些特定的性质
方法-------对象能做的事情
事件-------能响应发生在对象上的事情
     注意:对象只是一种特殊的数据

     2.  基本对象
        
         我们一般划分的角度还是从数据类型这方面
Number
String
Array
Math
Data  
这边我只是简单地罗列出来部分,具体的可以参考http://www.w3school.com.cn/js/js_obj_intro.asp
 
不过我这边还是想讲一下比较流行的一道前端面试题,也是我当初来百度面试的时候问我的(题目的来源好像是方荣大侠的某个web前端研发工程师编程能力成长之路的文档里面的)
废话少说

出题:
                       “输出字符串--今天是星期几”

 

var _str = ""; 
var _today = new Date().getDay(); 
if(_today == 0){ 
   _str = "今天是星期日"; 
}else if(_today  == 1){ 
  _str = "今天是星期一"; 
}else if(_today  == 2){ 
  _str = "今天是星期二"; 
}else if(_today  == 3){ 
  _str = "今天是星期三"; 
}else if(_today  == 4){ 
  _str = "今天是星期四"; 
}else if(_today  == 5){ 
  _str = "今天是星期五"; 
}else if(_today  == 6){ 
  _str = "今天是星期六"; 
} 

 

var _str ="今天是星期"; 

var _today=new Date().getDay(); 
switch(_today){ 
      case 0: 
           _str += "日"; 
           break; 
      case 1: 
           _str += "一"; 
           break; 
      case 2: 
           _str += "二"; 
           break; 
      case 3: 
           _str += "三"; 
           break; 
      case 4: 
           _str += "四"; 
           break; 
      case 5: 
           _str += "五"; 
           break; 
      case 6: 
           _str += "六"; 
           break; 
 
} 


var _str = "今天是星期"+"日一二三四五六".charAt(new Date().getDay()); 

  


 3.
下面介绍创建类和对象的模式
简单方式
        

var people ={}; 
Js代码 
      people.name = "steven"; 
      people.age = 23; 
      people.getName = function(){ 
           return "People's name is "+ this.name; 
     }; 
console.log(people.getName());          //People's name is steven 
console.log(people.age);                    //23 

  


不好的地方就是:在创建多个对象的场景下会产生 很多冗余的代码,耦合度不高 
 

工厂模式下

function makePeople(name,age,job){ 
     var _obj = {}; 
     _obj.name = name; 
     _obj.age =age; 
     _obj.job = job; 
    _obj.getName = function(){ 
        return "People's name is "+ this.name; 
   }  
    return _obj; 
} 
 
var webdesigner = makePeople("steven",23,"wendesigner"); 
console.log(webdesigner.getName );       //People's name is steven 
console.log(webdesigner.job)                //wendesigner 

  


 

Js代码 
不好的地方就是:实例化比较频繁 

原型模式(prototype)下

function People(){}; 
People.prototype = { 
       constructor :People, 
       name:"steven", 
       age:23, 
       job:"webdesigner", 
       getName:function(){ 
             return "People's name is "+this.name; 
      } 
} 
 
var webdesign = new People(); 
var carman = new People(); 
console.log(webdesign.getName());    //People's name is steven 
console.log(carman.getName());    //People's name is steven 

  


 
Js代码 
不好的地方就是:初始化参数不支持传递,还有就是原型的所有属性和方法会被所有的实例共享 

混合模式(原型+构造函数)下
 
 
 

function People(name.age.job){ 
Js代码 
this.name = name; 
Js代码 
       this.age = age; 
       this.job = job; 
}; 
People.prototype = { 
      constructor:People, 
      getName: function(){ 
           return "People's name is "+this.name; 
      } 
} 
 
var webdesigner  = new People("steven",23,"webdesigner"); 
var carman = new People("zyc",24,"carman"); 
console.log(webdesigner.getName())   //People's name is steven 
console.log(carman.getName())   //People's name is zyc 

  


 
Js代码 
不好的地方就是:对象的属性和方法也多是公用的 
 
 
闭包下的私有变量模式

(function(){ 
    var name =""; 
    People = function(val){ 
        name = val; 
   }; 
    People.prototype ={ 
       constructor:People, 
       getName:function(){ 
              return "People's name is "+ name ; 
      } 
   }; 
})(); 
 
 
var webdesigner = new People("steven"); 
console.log(webdesigner.name);           //undefined 
console.log(webdesigner.getName());      //People's name is steven 
 
var carman= new People("zyc"); 
console.log(carman.name);           //undefined 
console.log(carman.getName());      //People's name is zyc 
 

  

Js代码 
不好的地方就是:初级程度代码不是很让人理解 

转载自: 作者“zhangyaochun”

posted @ 2014-03-29 00:04  Arthur.Wang  阅读(...)  评论(...编辑  收藏