1. new Function
var test = new Function("(function(){console.log('hello!')})()");会在外面再包一层函数,获取不到返回值:

2. eval
var test = eval("(function(a, b){return a+b;})");能获取返回值:

var test = new Function("(function(){console.log('hello!')})()");会在外面再包一层函数,获取不到返回值:

var test = eval("(function(a, b){return a+b;})");能获取返回值:
