$.ajax({  
    type: 'post',  
    url: "maintain_findRoomByBuildingId.shtml",  
    cache: false,  
    data: {"buildingId":buildingId},  
    dataType: 'json',  
    success: function(data){  
      jQuery.each(data.roomList, function(i,item){  
        alert(item.id+","+item.name);  
      });  
    },  
    error: function(){  
      return;  
    }  
  });