promise

网上找到一段promise

    var Promise = function () {        this.thens = [];    };    Promise.prototype = {        resolve: function () {            var t = this.thens.shift(), n;            t && (n = t.apply(null, arguments), n instanceof Promise && (n.thens = this.thens));        },        then: function (n) {            return this.thens.push(n), this;        }    }

// 修改后