js基础（闭包实例）

1，常用发送短信的闭包实现：

function sms() {
	var count = 60;
	return {
		start: function() {
			if(count == 0) {
				count = 60;
				document.getElementById("time").innerHTML = count;
				return;
			} else {
				document.getElementById("time").innerHTML = count;
				count--;
			}
			var that = this;
			setTimeout(function() {
				that.start();
			}, 1000)
		},
		stop: function() {
			count = 60;
		}
	}
}
var sms = sms();
sms.start();

2，匿名自执行函数　

var data= {    
	 msg: "Helloween "   
};    
 (function(dm){    
	console.info(dm.msg)
})(data);

3,封装

var person = function(){    
    //变量作用域为函数内部，外部无法访问    
    var name = "default";       

    return {    
       getName : function(){    
           return name;    
       },    
       setName : function(newName){    
           name = newName;    
       }    
    }    
}();    

print(person.name);//直接访问，结果为undefined    
print(person.getName());    
person.setName("abruzzi");    
print(person.getName()); 

4,实现类和继承　

function Person(){    
    var name = "default";       

    return {    
       getName : function(){    
           return name;    
       },    
       setName : function(newName){    
           name = newName;    
       }    
    }    
    };   

    var p = new Person();
    p.setName("Tom");
    alert(p.getName());
    var Jack = function(){};
    //继承自Person
    Jack.prototype = new Person();
    //添加私有方法
    Jack.prototype.Say = function(){
        alert("Hello,my name is Jack");
    };
    var j = new Jack();
    j.setName("Jack");
    j.Say();
    alert(j.getName());