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Now I will bring you a basic introduction to JavaScript_object. Let me share it with you now and give it as a reference for everyone.
The base class of all Object classes
var obj = new Object(); var obj = {}; //实例化对象
There are two types of setting properties for objects:
1 .Use direct quantities: object.properties/methods, this method is intuitive and easy to understand
obj.name = '张三'; obj.age = 20; obj.sex = '男'; obj.say = function(){ alert("hello World"); }
2.Use "[]": object.['properties/methods '], when using this method, "" or '' must be added within the brackets, the method is strict
obj['birthday'] = '1989-08-07';
获取对象的属性或者方法:对象.属性名/方法 alert(obj.name); // 张三 alert(obj.age); // 20 obj.say(); // hello World
delete 操作符 删除对象的属性或方法的 delete obj.age; delete obj.say; alert(obj.age); //undified alert(obj.sex); //20 obj.say(); //报错,函数已被删除
Traverse a js object, for in statement
for(var attr in obj){ alert(attr + ":" + obj[attr]); //会按顺序将数组中的键值对打印,主要值,如果用对象.属性得到undified }
Constructor saves the creation function of the object
alert(obj.constructor); var o = []; alert(o.constructor);
hasOwnProperty(propertyName) 用于检测给定属性在对象中是否存在,返回boolean类型,在项目中有时会用到,需留意 var i = {}; i.sex = '男'; alert(i.hasOwnProperty('sex')); //true alert(i.hasOwnProperty('age')); //false
propertyIsEnumerable(propertyName)检测给定的属性是否能被for in 所枚举出来,返回boolean alert(i.propertyIsEnumerable('age')); //false 上面没有定义此属性
The above is what I compiled for everyone. I hope it will be helpful to everyone in the future.
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