          if(loading){
              $("#loading").remove();
              loading = false;
          }else{
              $('<div id="loading">'+
                '<span style="position: fixed; top: 50%;left: 50%;color: white;"><b>Loading...</b></span>'+
                '</div>')
                  .css({position: "fixed",
                        top: 0,
                        left: 0,
                        width: "100%",
                        height: "100%",
                        'background-color': 