error and no data messages for historical tab
diff --git a/planetstack/templates/admin/dashboard/hpc_historical.html b/planetstack/templates/admin/dashboard/hpc_historical.html
index e312ee9..2e3b85e 100644
--- a/planetstack/templates/admin/dashboard/hpc_historical.html
+++ b/planetstack/templates/admin/dashboard/hpc_historical.html
@@ -21,11 +21,10 @@
      function updateDataSourceUrl() {
          var sliceName = $("#historical_slicename :selected").text();
          var queryString = "/analytics/bigquery/?timeBucket=600&maxAge=86400&sum=@bytes_sent&avg=@cpu&groupBy=Time,city,@hostname,@site&slice=" + sliceName;
-         var loadingDiv = '<div class="loading">Loading ...</div>';
 
          $( "#control1").html("");
          $( "#control2").html("");
-         $( "#chart-site-agg" ).html(loadingDiv);
+         $( "#chart-site-agg" ).html("<div class='loading'>Loading ...</div>");
          $( "#chart-site-time" ).html("");
          $( "#chart-geo" ).html("");
 
@@ -191,6 +190,16 @@
          var format0dp = new google.visualization.NumberFormat({fractionDigits:0});
          var format2dp = new google.visualization.NumberFormat({fractionDigits:2});
 
+         if (response.isError()) {
+             $( "#chart-site-agg" ).html("<div class='loading'>Error while fetching data.</div>");
+             return;
+         }
+
+         if (response.getDataTable().getNumberOfRows() == 0) {
+             $( "#chart-site-agg" ).html("<div class='loading'>No data for this slice.</div>");
+             return;
+         }
+
          // Create a group for charts that will have a horizontal axis that is
          // time.