javascript 关闭页面提示

 1  window.onbeforeunload = function (e) {

 2             e = e || window.event;

 3             // For IE and Firefox prior to version 4 

 4             if (e) {

 5                 e.returnValue = '确定退出吗？';

 6             }

 7 

 8             // For Safari 

 9             return '确定退出吗？';

10         }