Your browser does not seem to support JavaScript. As a result, your viewing experience will be diminished, and you may not be able to execute some actions.
Please download a browser that supports JavaScript, or enable it if it's disabled (i.e. NoScript).
麻烦贴一个例子上来。请不要贴手册上那个，那个不能用。
按照手册用了，但是主核没有执行回调函数。