Javascript-从函数返回一个对象

Question

我想获得一个函数，提示用户输入信息，然后将该信息传递给对象。到目前为止，它似乎没有这样做。

// my object constructor 
 
var Person = function (firstName, lastName, areaCode, phone) { 
 
    this.firstName = firstName; 
 
    this.lastName = lastName; 
 
    this.areaCode = areaCode; 
 
    this.phone = phone; 
 
} 
 

 
// my function to get user info 
 
function getInfo() { 
 
    firstName = prompt("What is your first name: "); 
 
    lastName = prompt("What is your last name: "); 
 
    areaCode = prompt("What is your area code: "); 
 
    phone = prompt("What is your phone number: "); 
 
    var guy = Person(firstName, lastName, areaCode, phone); 
 
    return guy; 
 
} 
 

 
// calling the function 
 
getInfo(); 
 

 
// test to see if it actually worked 
 
document.writeln(guy.firstName);

Answer 1

你的代码有三个问题：

• 当实例构造函数，你必须使用new。
• 如果你在一个函数内声明一个变量（guy），它将不能从外部访问。你可以
  • 在外面声明它，并在函数内设置它的值。
  • 将其返回到外部。在这种情况下，您必须使用返回值。
• 您没有在getInfo中定义变量。然后，它只会在非严格模式下工作，并且会变成全局的，这可能是不好的。

// my object constructor 
 
var Person = function (firstName, lastName, areaCode, phone) { 
 
    this.firstName = firstName; 
 
    this.lastName = lastName; 
 
    this.areaCode = areaCode; 
 
    this.phone = phone; 
 
} 
 

 
// my function to get user info 
 
function getInfo() { 
 
    var firstName = prompt("What is your first name: "), 
 
     lastName = prompt("What is your last name: "), 
 
     areaCode = prompt("What is your area code: "), 
 
     phone = prompt("What is your phone number: "); 
 
    return new Person(firstName, lastName, areaCode, phone); 
 
} 
 

 
// calling the function 
 
var guy = getInfo(); 
 

 
// test to see if it actually worked 
 
document.writeln(guy.firstName);