Javascript-從函數返回一個對象

Question

我想獲得一個函數，提示用戶輸入信息，然後將該信息傳遞給對象。到目前爲止，它似乎沒有這樣做。

// 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

你的代碼有三個問題：

• 當實例構造函數，你必須使用new。
• 如果你在一個函數內聲明一個變量（guy），它將不能從外部訪問。你可以
  • 在外面聲明它，並在函數內設置它的值。
  • 將其返回到外部。在這種情況下，您必須使用返回值。
• 您沒有在getInfo中定義變量。然後，它只會在非嚴格模式下工作，並且會變成全局的，這可能是不好的。

// 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);