javaScript中this以及window对象和window对象的name属性

忘是亡心i 2022-11-10 14:55 190阅读 0赞

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2N6aDUwMA_size_16_color_FFFFFF_t_70][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2N6aDUwMA_size_16_color_FFFFFF_t_70 1][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2N6aDUwMA_size_16_color_FFFFFF_t_70 2][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2N6aDUwMA_size_16_color_FFFFFF_t_70 3][]

![20210319040415862.png][]

**一打开页面，即第1次运行，运行结果如下：**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2N6aDUwMA_size_16_color_FFFFFF_t_70 4][]

![20210319040756516.png][]

**第2次运行，运行结果如下：**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2N6aDUwMA_size_16_color_FFFFFF_t_70 5][]

![20210319041123548.png][]

<!DOCTYPE html>
    <html>
    <head>
    <meta charset="UTF-8">
    <title>javaScript中this以及window对象和window对象的name属性</title>
    <script type="text/javascript">
    //打开浏览器，执行本页面所有的代码，第一次执行和第二次执行，运行结果会不同，大家可以试一下
    
    //全局变量(全局变量是属于window对象的属性)
    var hometown = "江西省赣州市于都县渡江大道666666号";
    console.log(window.hometown, hometown);//window可以省略不写
    
    var salary = 19800.56;
    //19800.56 19800.56 19800.56
    console.log(salary, window['salary'], window.salary);
    //window['salary']这样写才对，如下这种写法不可以
    console.log(window[salary]);//undefined
    
    console.log(window, this);
    console.log(window == this, window === this); //true true
    
    function Dog(str) {
    	this.name = str;
    }
    
    var dog1 = new Dog('旺财');
    console.log(dog1.name); //结果  
    console.log(name); //结果
    
    //在js中window对象有name属性，name属性的值默认是""空字符
    console.log(window.name);
    console.log(name); //window可以省略不写
    
    function fn(str) {
    	console.log("hello" + str, this);
    	this.name = str;
    	this.age = 26;
    }
    //如果把下面这2行代码注释掉，运行效果会大不相同，大家可以试一试，会学习到一些意想不到的知识
    window.fn("令狐冲");
    fn("韦小宝");
    
    var f = new fn("张无忌");
    
    console.log(f.name, f.age);
    console.log(name);
    console.log(name, age);
    console.log(window.name, window.age);
    
    function Person(str) {
    	this.userName = str;
    	this.userAge = 12;
    }
    
    var p1 = new Person('杨过');
    console.log(p1.userName); //杨过
    // console.log(userName); //Uncaught ReferenceError: userName is not defined
    
    console.log(p1.userAge); //12
    // console.log(userAge); //Uncaught ReferenceError: userAge is not defined
    window.Person("段誉");
    console.log(userName, window.userName); //段誉 段誉
    console.log(userAge, window.userAge); //12 12
    
    Person("乔峰");
    console.log(userName, window.userName); //乔峰 乔峰
    console.log(userAge, window.userAge); //12 12
    
    console.log(window.name);
    
    function Cat(str) {
    	this.name = str;
    	//没有使用var关键字定义的变量是全局变量
    	hobby = "羽毛球"; //全局变量(全局变量是属于window对象的属性)
    }
    
    var catA = new Cat('Tom');
    console.log(catA.name);//Tom
    console.log(name);
    
    console.log(catA.hobby);//undefined
    console.log(hobby, window.hobby);//羽毛球 羽毛球
    </script>
    </head>
    <body style="background-color: #CCE8CF;">
    <h2>javaScript中this以及window对象和window对象的name属性</h2>
    <div id="div1" style="background-color: Wheat; height: 200px;">
    </div>
    </body>
    </html>

javaScript中this以及window对象和window对象的name属性的知识点，大家最好是自己去写一写，测一测，自己去理解一下。

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[20210319040415862.png]: https://img-blog.csdnimg.cn/20210319040415862.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2N6aDUwMA_size_16_color_FFFFFF_t_70 4]: https://img-blog.csdnimg.cn/20210319040700415.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2N6aDUwMA==,size_16,color_FFFFFF,t_70
[20210319040756516.png]: https://img-blog.csdnimg.cn/20210319040756516.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2N6aDUwMA_size_16_color_FFFFFF_t_70 5]: https://img-blog.csdnimg.cn/20210319041039871.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2N6aDUwMA==,size_16,color_FFFFFF,t_70
[20210319041123548.png]: https://img-blog.csdnimg.cn/20210319041123548.png