>全局属性和方法： "util", "set", "delete", "nextTick", "options", "use", "mixin", "cid", "extend", "component", "directive", "filter", "version", "compile" Vue.util:工具函数 (core/util/index) Vue.set : 响应设置 (core/observer/index set); Vue.delete : 响应删除(core/observer/index delete); Vue.nextTick : 延迟执行(core/util/index nextTick); Vue.config : 配置项，通过defineProperty()中的set禁止用户修改Vue.config Vue.options: components: KeepAlive Transition TransitionGroup directives: model show filters: Vue.use(): 安装插件 Vue.mixin(options): options合并到Vue.options对象上 Vue.extend(options) : 返回一个继承Vue的字SubVue对象；