$('body').bind('beforeunload',function(){
   //do something
});

但是，这不会保存任何信息以供以后使用，除非您计划将其保存在cookie的某个地方或本地存储），并且卸载事件并不总是在所有浏览器中触发。

But this wont save any info for later, unless you were planning on saving that in a cookie somewhere (or local storage) and the unload event does not always fire in all browsers.

示例： http://jsfiddle.net/maniator/qpK7Y/

代码：

$(window).bind('beforeunload',function(){

     //save info somewhere

    return 'are you sure you want to leave?';

});