JavaScript 学习（一）

创建一个对象

 <script type="text/javaScript">
   var newObject=new Object();
   //创建一个对象
    newObject.firstName="frank";
    //增加一个firstName属性
    newObject.sayName=function(){
        alert(this.firstName);
    }
     //添加一个sayName方法
//调用sayName方法
//    newObject.sayName();
//    newObject["sayName"]();
    var FirstName=newObject["firstName"];
    var whatFunction;
//    if(whatVolume==1){
//        whatFunction="sayName";
//    }else if(whatVolume==2){
//        whatFunction="sayLoudly"
//    }
//    newObject[whatFunction]();
    function sayLoudly(){
        alert(this.firstName.toUpperCase());
    }
    newObject.sayLoudly=sayLoudly;
    //另一种方式添加方法
    newObject["sayLoudly"]();
 </script>

利用json（javaScript Object Notation）创建对象和上面同样的效果。

   function sayLoudly(){
        alert(this.firstName.toUpperCase());
    }
    var newObject={
        firstName:"frank",
        sayName:function(){alert(this.firstName);},
        sayLoudly:sayLoudly
    };
//也可以这样
   var newObject={
        firstName:"frank",
        sayName:function(){alert(this.firstName);},
        sayLoudly:sayLoudly,
        lastName:{
            lastName:"ziggy",
            sayName:function(){alert(this.lastName);}
        }
    };
    newObject.lastName.sayName();

这样也ok

   function sayLoudly(){
        alert(this.name.toUpperCase());
    }
   function sayName(){
       alert(this.name);
   }
    var newObject={
        name:"frank",
        sayName:sayName,
        sayLoudly:sayLoudly,
        lastName:{
            name:"ziggy",
            sayName:sayName
        }
    };
    newObject.lastName.sayName();

JavaScript 中的类，还有构造方法。。。

   function newClass(){
        alert("constructor");
        this.firstName="frank";
        this.sayName=function(){alert(this.firstName);}
       // return this;
    }
    //var nc=newClass();
    var nc=new newClass();
    //nc.firstName="ziggy";  is ok
    nc.sayName();

还可以这样来构造类

   function newClass(){
     this.firstName="frank";
   }
    newClass.prototype.sayName=function(){
        alert(this.firstName);
    }
    var nc=new newClass();
    nc.firstName="ziggy";
    nc.sayName();
    var nc2=new newClass();
    nc2.sayName();

一般用prototypes来添加方法，这样不管有多少个实例，在内存中只有一个sayName方法。