函数的声明方式

1.函数构造器 

 new Function(……) 

不常用

var add = new Function("first", "second", "return first + second");

console.log(add(1, 1)); // 2

2.函数声明式

function doSomething() { }

常用

function doSomething() {

    console.log('this is doSomething.');

}

doSomething();

3.匿名函数表达式

var doAnotherThing = function() { }

常用

var doAnotherThing = function() {

    console.log('this is doAnotherThing.');

};

doAnotherThing();