jquery mobile 的 panel中的事件绑定怎么用？

Question

jqm API中的panel关闭前的事件beforeclose怎么用，API的文档照着写不起作用：Code examples:Initialize the panel with the beforeclose callback specified:$( ".selector" ).panel({ beforeclose: function( event, ui ) {}});Bind an event listener to the panelbeforeclose event:$( ".selector" ).on( "panelbeforeclose", function( event, ui ) {} );