取到顶层对象的两种方法

ES6

(typeof window !== 'undefined' ? window : (typeof process === 'object' && typeof require === 'function' && typeof global === 'object')? global : this);

var getGlobal = function(){
    if(typeof self !== 'undefined'){return self;}
    if(typeof window !== 'undefined'){return window;}
    if(typeof global !== 'undefined'){return global;}
    throw new Error('无法定位全局对象');
};