创建能够记住其状态的函数

function greetingMaker(greeting){
function addName(name){
return greeting+ " " + name;
}
return addName;
}
//创建一个新的局部函数
var daytimeGreeting = greetingMaker("Good Day to you");
var nightGreeting = greetingMaker("Good Evening");
//如果是白天
console.log(daytimeGreeting("Marry"));
//如果是黑夜
console.log(nightGreeting("Dock"));
//输出
"Good Day to you Marry"
"Good Evening Dock"