extjs button 似乎没有执行hanel，这是为什么？

Question

  var win = new Ext.create('Ext.window.Window', {
            title: '报表',
            height: 500,
            width: 600,
            layout: 'fit',
            tbar: [startDate, endDate],
            buttons: [
              { text: '立即体检',
                  handel: function () {
                      Ext.Ajax.request({
                          url: 'core/WebService.asmx/Time',
                          headers: {
                              'Content-Type': 'application/json; charset=utf-8'
                          },
                          method: 'POST',
                          jsonData: {
                              start: Ext.Date.format(startDate.getValue(), 'Y-m-d'),
                              end: Ext.Date.format(endDate.getValue(), 'Y-m-d') + ' 23:59:59.999'
                          }                      });
                  }
              }
            ]
            //items: {   }     
        })        win.show();