Object的属性(firebug中没有找到)
var pro={
city:"shanghai",
list:[,,,,]
}
var Person=function(name,age){
this.name=name;
this.age=age;
this.arr=[,,,,];
}
Person.prototype=pro;
var p=new Person("hongda",);
console.log("hasOwnProperty:");
console.log(p.hasOwnProperty("name"))
console.log(p.hasOwnProperty("city"))
console.log("isPrototypeOf:");
console.log(pro.isPrototypeOf(p));
console.log(Person.prototype.isPrototypeOf(p));
console.log("propertyIsEnumerable:");
console.log(p.propertyIsEnumerable("arr"));
console.log(p.propertyIsEnumerable("list"));
Object静态方法:
Object.create
var obj=Object.create({name:"hongda",age:});
console.dir(obj);
Object.getPrototypeOf:
var pp=Object.getPrototypeOf(p);
console.dir(pp);
console.log(pp===pro);
Object.getOwnPropertyDescriptor:
Object.getOwnPropertyNames:
var desc=Object.getOwnPropertyDescriptor(p,"name");
console.dir(desc); var names=Object.getOwnPropertyNames(p);
console.dir(names);
Object.keys(obj)
跟Object.getOwnPropertyNames(obj)差不多,区别就是Object.keys只适用于可枚举的属性,而Object.getOwnPropertyNames返回对象自动的全部属性名称。
具体的可以看链接http://www.cnblogs.com/chollaflower/p/3203210.html
Object.defineProperty:
Object.defineProperty(p, 'english_Name', {
set : function(n){
console.log('set 访问器');
this.nameValue = n; //一个新的属性,如果同样是name的话,就死循环了。
},
get : function(){
console.log('get 访问器');
return 'my english_Name is ' + this.nameValue;
},
// value : 'Tom', //如果在这里有value或writable特性,就会报错:Uncaught TypeError: Invalid property. A property cannot both have accessors and be writable or have a value。
//writable: true,
enumerable: false,
configurable: false
});
p.english_Name="Tom";
console.dir(p);
var desc=Object.getOwnPropertyDescriptor(p,"english_Name");
console.dir(desc);
当value或writable使用时,报错
不可以同set或get同时使用
p.english_Name="Tom“;
不写的话,console.dir(p)不会显示。
之所以显示nameValue是因为在set中设置的。
Object.defineProperties:
var p={};
Object.defineProperties(p, {
sex: {
value: 'boy',
writable: true,
enumerable: false,
configurable: false
},
age2: {
set: function(x) {
this.age2Value = x;
},
get: function() {
return this.age2Value;
}
}
});
console.dir(p);
var desc=Object.getOwnPropertyDescriptor(p,"sex");
console.dir(desc);
console.log(p.hasOwnProperty("sex"));
console.log(p.hasOwnProperty("city"));
console.log(p.hasOwnProperty("age2"));
console.dir(p);
console.log(p.sex);
不清楚为什么console.dir()不能查看到添加的属性。
http://www.cnblogs.com/chollaflower/p/3202731.html
Object.preventExtensions(object)
防止新的属性添加到对象
Object.isExtensible(object)
是否可添加属性到对象
console.log(Object.isExtensible(p)); //true
Object.preventExtensions(p);
console.log(Object.isExtensible(p)); //false
Object.seal(object)
不能添加和删除属性
Object.isSealed(object)
console.log(Object.isSealed(p));//false
Object.seal(p);
console.log(Object.isSealed(p));//true
完全封死对象,可以
Object.freeze(object)
防止现有属性和属性值的修改,并防止新特性的添加。
Object.isFrozen(object)
console.log(Object.isFrozen(p));//false
Object.freeze(p);
console.log(Object.isFrozen(p));//true
http://blog.csdn.net/shyleoking/article/details/7316174
http://www.cnblogs.com/chollaflower/archive/2013/07/20/3203210.html
http://www.cnblogs.com/rexmzk/archive/2012/12/14/2815112.html
http://msdn.microsoft.com/zh-tw/library/kb6te8d3(v=vs.94).aspx