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  • JavaScript之new与不new的区别

    new 和不 new的区别:

    •  如果 new 了函数内的 this 会指向当前这个 person 并且就算函数内部不 return 也会返回一个对象。
    •  如果不 new 的话函数内的 this 指向的是 window。
    function person(firstname,lastname,age,eyecolor)
    {
        this.firstname=firstname;
        this.lastname=lastname;
        this.age=age;
        this.eyecolor=eyecolor;
        return [this.firstname,this.lastname,this.age,this.eyecolor,this] 
    }
    
    var myFather=new person("John","Doe",50,"blue");
    var myMother=person("Sally","Rally",48,"green");
    console.log(myFather) 
    console.log(typeof myFather) 
    console.log(myMother) 
    console.log(typeof myMother) 

    function person(firstname,lastname,age,eyecolor)
    {
        this.firstname=firstname;
        this.lastname=lastname;
        this.age=age;
        this.eyecolor=eyecolor;
    //     return [this.firstname,this.lastname,this.age,this.eyecolor,this] 
    }
    
    var myFather=new person("John","Doe",50,"blue");
    var myMother=person("Sally","Rally",48,"green");
    console.log(myFather) 
    console.log(typeof myFather) 
    console.log(myMother) 
    console.log(typeof myMother) 

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  • 原文地址:https://www.cnblogs.com/sunupo/p/15475987.html
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