JavaScript函数的返回值

function add(a, b) {
  return a + b;
}

var result = add(2, 3); // 返回值为5

function greet(name) {
  return "Hello, " + name + "!";
}

var message = greet("John"); // 返回值为"Hello, John!"

function isEven(num) {
  return num % 2 === 0;
}

var isEvenNumber = isEven(4); // 返回值为true

function createPerson(name, age) {
  return {
    name: name,
    age: age,
    greet: function() {
      return "Hello, my name is " + this.name + " and I'm " + this.age + " years old.";
    }
  };
}

var person = createPerson("Alice", 25);
console.log(person.name); // 输出"Alice"
console.log(person.greet()); // 输出"Hello, my name is Alice and I'm 25 years old."