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”