diff --git a/caravel/assets/visualizations/heatmap.js b/caravel/assets/visualizations/heatmap.js
index 55ec7ef46..18aa2eea3 100644
--- a/caravel/assets/visualizations/heatmap.js
+++ b/caravel/assets/visualizations/heatmap.js
@@ -21,6 +21,7 @@ function heatmapVis(slice) {
     };
 
     d3.json(slice.jsonEndpoint(), function (error, payload) {
+      slice.container.html('');
       var matrix = {};
       if (error) {
         slice.error(error.responseText);
diff --git a/caravel/assets/visualizations/nvd3_vis.js b/caravel/assets/visualizations/nvd3_vis.js
index 40bf3ebe2..a6ffe54b2 100644
--- a/caravel/assets/visualizations/nvd3_vis.js
+++ b/caravel/assets/visualizations/nvd3_vis.js
@@ -14,222 +14,222 @@ function nvd3Vis(slice) {
 
   var render = function () {
     $.getJSON(slice.jsonEndpoint(), function (payload) {
-        var fd = payload.form_data;
-        var viz_type = fd.viz_type;
-        var f = d3.format('.3s');
+      var fd = payload.form_data;
+      var viz_type = fd.viz_type;
+      var f = d3.format('.3s');
+      slice.container.html('');
 
-        nv.addGraph(function () {
-          if (!chart) {
-            switch (viz_type) {
-              case 'line':
-                if (fd.show_brush) {
-                  chart = nv.models.lineWithFocusChart();
-                  chart.lines2.xScale(d3.time.scale.utc());
-                  chart.x2Axis
-                      .showMaxMin(fd.x_axis_showminmax)
-                      .staggerLabels(false);
-                } else {
-                  chart = nv.models.lineChart();
-                }
-                // To alter the tooltip header
-                // chart.interactiveLayer.tooltip.headerFormatter(function(){return '';});
-                chart.xScale(d3.time.scale.utc());
-                chart.interpolate(fd.line_interpolation);
-                chart.xAxis
-                    .showMaxMin(fd.x_axis_showminmax)
-                    .staggerLabels(false);
-                break;
-
-              case 'bar':
-                chart = nv.models.multiBarChart()
-                    .showControls(true)
-                    .groupSpacing(0.1);
-
-                chart.xAxis
-                    .showMaxMin(false)
-                    .staggerLabels(true);
-
-                chart.stacked(fd.bar_stacked);
-                break;
-
-              case 'dist_bar':
-                chart = nv.models.multiBarChart()
-                    .showControls(true) //Allow user to switch between 'Grouped' and 'Stacked' mode.
-                    .reduceXTicks(false)
-                    .rotateLabels(45)
-                    .groupSpacing(0.1); //Distance between each group of bars.
-
-                chart.xAxis
-                    .showMaxMin(false);
-
-                chart.stacked(fd.bar_stacked);
-                break;
-
-              case 'pie':
-                chart = nv.models.pieChart();
-                colorKey = 'x';
-                chart.valueFormat(f);
-                if (fd.donut) {
-                  chart.donut(true);
-                  chart.labelsOutside(true);
-                }
-                chart.labelsOutside(true);
-                chart.cornerRadius(true);
-                break;
-
-              case 'column':
-                chart = nv.models.multiBarChart()
-                    .reduceXTicks(false)
-                    .rotateLabels(45);
-                break;
-
-              case 'compare':
-                chart = nv.models.cumulativeLineChart();
-                chart.xScale(d3.time.scale.utc());
-                chart.xAxis
-                    .showMaxMin(false)
-                    .staggerLabels(true);
-                break;
-
-              case 'bubble':
-                var row = function (col1, col2) {
-                  return "<tr><td>" + col1 + "</td><td>" + col2 + "</td></tr>";
-                };
-                chart = nv.models.scatterChart();
-                chart.showDistX(true);
-                chart.showDistY(true);
-                chart.tooltip.contentGenerator(function (obj) {
-                  var p = obj.point;
-                  var s = "<table>";
-                  s += '<tr><td style="color:' + p.color + ';"><strong>' + p[fd.entity] + '</strong> (' + p.group + ')</td></tr>';
-                  s += row(fd.x, f(p.x));
-                  s += row(fd.y, f(p.y));
-                  s += row(fd.size, f(p.size));
-                  s += "</table>";
-                  return s;
-                });
-                chart.pointRange([5, fd.max_bubble_size * fd.max_bubble_size]);
-                break;
-
-              case 'area':
-                chart = nv.models.stackedAreaChart();
-                chart.style(fd.stacked_style);
-                chart.xScale(d3.time.scale.utc());
-                chart.xAxis
-                    .showMaxMin(false)
-                    .staggerLabels(true);
-                break;
-
-              case 'box_plot':
-                colorKey = 'label';
-                chart = nv.models.boxPlotChart();
-                chart.x(function (d) {
-                  return d.label;
-                });
-                chart.staggerLabels(true);
-                chart.maxBoxWidth(75); // prevent boxes from being incredibly wide
-                break;
-
-              default:
-                throw new Error("Unrecognized visualization for nvd3" + viz_type);
+      nv.addGraph(function () {
+        switch (viz_type) {
+          case 'line':
+            if (fd.show_brush) {
+              chart = nv.models.lineWithFocusChart();
+              chart.lines2.xScale(d3.time.scale.utc());
+              chart
+              .x2Axis
+              .showMaxMin(fd.x_axis_showminmax)
+              .staggerLabels(false);
+            } else {
+              chart = nv.models.lineChart();
             }
-          }
+            // To alter the tooltip header
+            // chart.interactiveLayer.tooltip.headerFormatter(function(){return '';});
+            chart.xScale(d3.time.scale.utc());
+            chart.interpolate(fd.line_interpolation);
+            chart.xAxis
+            .showMaxMin(fd.x_axis_showminmax)
+            .staggerLabels(false);
+            break;
 
-          if ("showLegend" in chart && typeof fd.show_legend !== 'undefined') {
-            chart.showLegend(fd.show_legend);
-          }
+          case 'bar':
+            chart = nv.models.multiBarChart()
+            .showControls(true)
+            .groupSpacing(0.1);
 
-          var height = slice.height();
-          height -= 15;  // accounting for the staggered xAxis
+            chart.xAxis
+            .showMaxMin(false)
+            .staggerLabels(true);
 
-          chart.height(height);
-          slice.container.css('height', height + 'px');
+            chart.stacked(fd.bar_stacked);
+            break;
 
-          if ((viz_type === "line" || viz_type === "area") && fd.rich_tooltip) {
-            chart.useInteractiveGuideline(true);
-          }
-          if (fd.y_axis_zero) {
-            chart.forceY([0]);
-          } else if (fd.y_log_scale) {
-            chart.yScale(d3.scale.log());
-          }
-          if (fd.x_log_scale) {
-            chart.xScale(d3.scale.log());
-          }
-          var xAxisFormatter = null;
-          if (viz_type === 'bubble') {
-            xAxisFormatter = d3.format('.3s');
-          } else if (fd.x_axis_format === 'smart_date') {
-            xAxisFormatter = px.formatDate;
-            chart.xAxis.tickFormat(xAxisFormatter);
-          } else if (fd.x_axis_format !== undefined) {
-            xAxisFormatter = px.timeFormatFactory(fd.x_axis_format);
-            chart.xAxis.tickFormat(xAxisFormatter);
-          }
+          case 'dist_bar':
+            chart = nv.models.multiBarChart()
+            .showControls(true) //Allow user to switch between 'Grouped' and 'Stacked' mode.
+            .reduceXTicks(false)
+            .rotateLabels(45)
+            .groupSpacing(0.1); //Distance between each group of bars.
 
-          if (chart.hasOwnProperty("x2Axis")) {
-            chart.x2Axis.tickFormat(xAxisFormatter);
-            height += 30;
-          }
+            chart.xAxis
+            .showMaxMin(false);
 
-          if (viz_type === 'bubble') {
-            chart.xAxis.tickFormat(d3.format('.3s'));
-          } else if (fd.x_axis_format === 'smart_date') {
-            chart.xAxis.tickFormat(px.formatDate);
-          } else if (fd.x_axis_format !== undefined) {
-            chart.xAxis.tickFormat(px.timeFormatFactory(fd.x_axis_format));
-          }
-          if (chart.yAxis !== undefined) {
-            chart.yAxis.tickFormat(d3.format('.3s'));
-          }
+            chart.stacked(fd.bar_stacked);
+            break;
 
-          if (fd.contribution || fd.num_period_compare || viz_type === 'compare') {
-            chart.yAxis.tickFormat(d3.format('.3p'));
-            if (chart.y2Axis !== undefined) {
-              chart.y2Axis.tickFormat(d3.format('.3p'));
+          case 'pie':
+            chart = nv.models.pieChart();
+            colorKey = 'x';
+            chart.valueFormat(f);
+            if (fd.donut) {
+              chart.donut(true);
+              chart.labelsOutside(true);
             }
-          } else if (fd.y_axis_format) {
-            chart.yAxis.tickFormat(d3.format(fd.y_axis_format));
+            chart.labelsOutside(true);
+            chart.cornerRadius(true);
+            break;
 
-            if (chart.y2Axis !== undefined) {
-              chart.y2Axis.tickFormat(d3.format(fd.y_axis_format));
-            }
-          }
-          chart.color(function (d, i) {
-            return px.color.category21(d[colorKey]);
-          });
+          case 'column':
+            chart = nv.models.multiBarChart()
+            .reduceXTicks(false)
+            .rotateLabels(45);
+            break;
 
-          var svg = d3.select(slice.selector).select("svg");
-          if (svg.empty()) {
-            svg = d3.select(slice.selector).append("svg");
-          }
+          case 'compare':
+            chart = nv.models.cumulativeLineChart();
+            chart.xScale(d3.time.scale.utc());
+            chart.xAxis
+            .showMaxMin(false)
+            .staggerLabels(true);
+            break;
 
-          svg
-            .datum(payload.data)
-            .transition().duration(500)
-            .attr('height', height)
-            .call(chart);
+          case 'bubble':
+            var row = function (col1, col2) {
+              return "<tr><td>" + col1 + "</td><td>" + col2 + "</td></tr>";
+            };
+            chart = nv.models.scatterChart();
+            chart.showDistX(true);
+            chart.showDistY(true);
+            chart.tooltip.contentGenerator(function (obj) {
+              var p = obj.point;
+              var s = "<table>";
+              s += '<tr><td style="color:' + p.color + ';"><strong>' + p[fd.entity] + '</strong> (' + p.group + ')</td></tr>';
+              s += row(fd.x, f(p.x));
+              s += row(fd.y, f(p.y));
+              s += row(fd.size, f(p.size));
+              s += "</table>";
+              return s;
+            });
+            chart.pointRange([5, fd.max_bubble_size * fd.max_bubble_size]);
+            break;
 
-          return chart;
-        });
+          case 'area':
+            chart = nv.models.stackedAreaChart();
+            chart.style(fd.stacked_style);
+            chart.xScale(d3.time.scale.utc());
+            chart.xAxis
+            .showMaxMin(false)
+            .staggerLabels(true);
+            break;
 
-        slice.done(payload);
-      })
-      .fail(function (xhr) {
-        slice.error(xhr.responseText);
+          case 'box_plot':
+            colorKey = 'label';
+            chart = nv.models.boxPlotChart();
+            chart.x(function (d) {
+              return d.label;
+            });
+            chart.staggerLabels(true);
+            chart.maxBoxWidth(75); // prevent boxes from being incredibly wide
+            break;
+
+          default:
+            throw new Error("Unrecognized visualization for nvd3" + viz_type);
+      }
+
+      if ("showLegend" in chart && typeof fd.show_legend !== 'undefined') {
+        chart.showLegend(fd.show_legend);
+      }
+
+      var height = slice.height();
+      height -= 15;  // accounting for the staggered xAxis
+
+      chart.height(height);
+      slice.container.css('height', height + 'px');
+
+      if ((viz_type === "line" || viz_type === "area") && fd.rich_tooltip) {
+        chart.useInteractiveGuideline(true);
+      }
+      if (fd.y_axis_zero) {
+        chart.forceY([0]);
+      } else if (fd.y_log_scale) {
+        chart.yScale(d3.scale.log());
+      }
+      if (fd.x_log_scale) {
+        chart.xScale(d3.scale.log());
+      }
+      var xAxisFormatter = null;
+      if (viz_type === 'bubble') {
+        xAxisFormatter = d3.format('.3s');
+      } else if (fd.x_axis_format === 'smart_date') {
+        xAxisFormatter = px.formatDate;
+        chart.xAxis.tickFormat(xAxisFormatter);
+      } else if (fd.x_axis_format !== undefined) {
+        xAxisFormatter = px.timeFormatFactory(fd.x_axis_format);
+        chart.xAxis.tickFormat(xAxisFormatter);
+      }
+
+      if (chart.hasOwnProperty("x2Axis")) {
+        chart.x2Axis.tickFormat(xAxisFormatter);
+        height += 30;
+      }
+
+      if (viz_type === 'bubble') {
+        chart.xAxis.tickFormat(d3.format('.3s'));
+      } else if (fd.x_axis_format === 'smart_date') {
+        chart.xAxis.tickFormat(px.formatDate);
+      } else if (fd.x_axis_format !== undefined) {
+        chart.xAxis.tickFormat(px.timeFormatFactory(fd.x_axis_format));
+      }
+      if (chart.yAxis !== undefined) {
+        chart.yAxis.tickFormat(d3.format('.3s'));
+      }
+
+      if (fd.contribution || fd.num_period_compare || viz_type === 'compare') {
+        chart.yAxis.tickFormat(d3.format('.3p'));
+        if (chart.y2Axis !== undefined) {
+          chart.y2Axis.tickFormat(d3.format('.3p'));
+        }
+      } else if (fd.y_axis_format) {
+        chart.yAxis.tickFormat(d3.format(fd.y_axis_format));
+
+        if (chart.y2Axis !== undefined) {
+          chart.y2Axis.tickFormat(d3.format(fd.y_axis_format));
+        }
+      }
+      chart.color(function (d, i) {
+        return px.color.category21(d[colorKey]);
       });
-  };
 
-  var update = function () {
-    if (chart && chart.update) {
-      chart.update();
-    }
-  };
+      var svg = d3.select(slice.selector).select("svg");
+      if (svg.empty()) {
+        svg = d3.select(slice.selector).append("svg");
+      }
 
-  return {
-    render: render,
-    resize: update
-  };
+      svg
+      .datum(payload.data)
+      .transition().duration(500)
+      .attr('height', height)
+      .call(chart);
+
+      return chart;
+    });
+
+    slice.done(payload);
+  })
+  .fail(function (xhr) {
+    slice.error(xhr.responseText);
+  });
+};
+
+var update = function () {
+  if (chart && chart.update) {
+    chart.update();
+  }
+};
+
+return {
+  render: render,
+  resize: update
+};
 }
 
 module.exports = nvd3Vis;