Javascript-从函数返回对象

Question

I am trying to get a function that prompts a user for info and then passes that info to an object. So far it does not seem to be doing that.

 // 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

Your code had three problems:

• When you instantiate a constructor, you must use new .
• If you declare a variable ( guy ) inside a function, it won't be accessible from the outside. You can
  • Declare it outside, and set its value inside the function.
  • Return it to the outside. In this case you must use the return value.
• You didn't define variables inside getInfo . Then, it will only work in non strict mode, and they will become globals, which may be bad.

 // 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);