转自：https://blog.csdn.net/lishk314/article/details/41541797
查看API：
Fires when this button is clicked, before the configured handler is invoked. Execution of the handler may be vetoed by returning false to this event.
单击按钮的时候触发的事件，在 handler配置被调用前触发，而handler配置将返回一个 false代码不执行。
A function called when the button is clicked (can be used instead of click event).
当点击按钮是触发的函数（可以用于代替click事件）.
相关文章：
http://nneverwei.iteye.com/blog/854396
