Detailed explanation of some usages of javascript objects

This object is not that object. Continuation of the second update. .

Yesterday we talked about the basic concepts and creation of objects. Today we will talk about its other methods:

1. Two ways to access properties: dot syntax and [] syntax

 1 var dog =new Object(); 2 dog.name="阿黄"; 3 dog.age="2"; 4              5 //点语法用来访问对象的属性和方法 6 alert(dog.name); 7              8 //[]语法来访问对象属性 9 alert(dog["name"]);//var a="name";alert(dog[a]);10             11 //dog.name=dog["name"];  他俩是等价的

Both dot syntax and [ ] syntax can access the properties of an object, but there are also differences:

　　1. Dot syntax mainly conforms to the variable naming rules;

　　2.[ ] syntax can use variables;

　　3.[ ] syntax can use invalid js characters; #　　　4. Dot syntax can be completely replaced with [ ] syntax, but not vice versa;

　　　5. [ ] syntax can use numbers, keywords, and reserved words to access object properties, but dot syntax cannot.

2. Use

for in

to traverse the object

1 //对象属性的遍历，Key是属性名2     for(var Key in dog){3         console.log(dog[Key]);4         //dog[key]==dog[属性名]5                 //console.log(Key);6     }

3.

delete

Delete attributes

##　4. hasOwnProperty()

This method can be used to detect whether the object has a certain local property, and the return value is TRUE or FALSE

　　

　5. instanceof

This method can be used to detect the relationship between instance objects and prototypes.

　　　　

　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　

　　　　　

　　　　　　　　　　　　　　　　　　　　　　　　　　　ute git by . Will update after finishing it!

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