new 和不 new的區別：

• 如果 new 了函式內的 this 會指向當前這個 person 並且就算函式內部不 return 也會返回一個物件。
• 如果不 new 的話函式內的 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)