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This time I will bring you the use of JS objects. What are the precautions when using JS objects. The following is a practical case, let’s take a look.
Object:
- 是复合类型,由简单数据类型和复合数据类型组成的。 - 由一对{ }包起来的, - 0对或者多对 键名和键值 组成的对, - 每对键值对 之间用","隔开,最后一个不要加","
Method 1: Through ConstructorCreate object
new Object();
Method 2 : Object literal creates an object
{ };
Method 1: Pass"."
<script> //通过构造函数创建对象 var obj= new Object(); //为对象添加属性 obj.a=2; console.log(obj);//{a: 1} //通过对象字面量创建对象 var t={}; //为对象添加属性 t.a=2; console.log(t);//{a: 1} </script>
Method 2:"[ ]"
<script> //通过构造函数创建对象 var obj= new Object(); //为对象添加属性 obj.["a"]=2; console.log(obj);//{a: 1} //通过对象字面量创建对象 var t={}; //为对象添加属性 t.["a"]=2; console.log(t);//{a: 1} </script>
Method 3: Write directly inside
<script> var obj= { name: "k", age: 12, gender: "male" } console.log(obj);//{name: "k", age: 12, gender: "male"} </script>
Obtaining object values
- 方式一:对象.键名(属性名); - 方式二:对象["键名"];
Use of in:
属性名 in 对象名 检测 在 对象中 是否 含有此属性名。
eg:
<script> var obj={ name:"L"; age:22; }; console.log(age in obj);//true console.log(gender in obj);//false </script>
Use of for in:
Traversal All properties within object feel like a cycle.
<script> var obj={ name:"k", age:21, gender:"women" }; // i是指对象的属性名,会遍历对象的属性值。 for (var i in obj){ console.log("第"+i+"项的属性值为:"+obj[i]); } var attr=[1,2,3,4]; for (var i in attr){ console.log("第"+i+"项值为:"+attr[i]); } </script>
The screenshot of the result is:
I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the PHP Chinese website!
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