//首先，创建通用诗的生成函数；它将作为下面的getUserInput函数的回调函数

    function genericPoemMaker(name, gender) {

        console.log(name + " is finer than fine wine.");

        console.log("Altruistic and noble for the modern time.");

        console.log("Always admirably adorned with the latest style.");

        console.log("A " + gender + " of unfortunate tragedies who still manages a perpetual smile");

    }

        //callback，参数的最后一项，将会是我们在上面定义的genericPoemMaker函数

        function getUserInput(firstName, lastName, gender, callback) {

            var fullName = firstName + " " + lastName;

            // Make sure the callback is a function

            if (typeof callback === "function") {

            // Execute the callback function and pass the parameters to it

            callback(fullName, gender);

            }

        }

getUserInput("Michael", "Fassbender", "Man", genericPoemMaker);

 // 输出 /* Michael Fassbender is finer than fine wine. Altruistic and noble for the modern time. Always admirably adorned with the latest style. A Man of unfortunate tragedies who still manages a perpetual smile. */


我们可以换一个回调函数试试：

function greetUser(customerName, sex)  {

   var salutation  = sex && sex === "Man" ? "Mr." : "Ms.";

  console.log("Hello, " + salutation + " " + customerName);

}

// 将greetUser作为一个回调函数

getUserInput("Bill", "Gates", "Man", greetUser);

// 这里是输出

Hello, Mr. Bill Gates