ajax timeout 断网处理

$.ajax({
   url:'fghjkld',
   type:'POST',
   data:{},    
   timeout:'3000',
   success:function(data){},
   error:function(jqXHR, textStatus, errorThrown){
          if(textStatus == 'timeout'){
              alert('超时事件！');
        } 
    }
})    

　　

http://stackoverflow.com/questions/5225597/set-timeout-for-ajax-jquery