diff --git a/kfet/static/kfet/js/statistic.js b/kfet/static/kfet/js/statistic.js
index 9baa08c4..23d66efe 100644
--- a/kfet/static/kfet/js/statistic.js
+++ b/kfet/static/kfet/js/statistic.js
@@ -1,28 +1,15 @@
-(function($){
+(function ($) {
     window.StatsGroup = function (url, target) {
         // a class to properly display statictics
 
         // url : points to an ObjectResumeStat that lists the options through JSON
         // target : element of the DOM where to put the stats
 
-        var self = this;
         var element = $(target);
         var content = $("<div class='full'>");
         var buttons;
 
-        function dictToArray (dict, start) {
-            // converts the dicts returned by JSONResponse to Arrays
-            // necessary because for..in does not guarantee the order
-            if (start === undefined) start = 0;
-            var array = new Array();
-            for (var k in dict) {
-                array[k] = dict[k];
-            }
-            array.splice(0, start);
-            return array;
-        }
-
-        function handleTimeChart (data) {
+        function handleTimeChart(data) {
             // reads the balance data and put it into chartjs formatting
             chart_data = new Array();
             for (var i = 0; i < data.length; i++) {
@@ -36,7 +23,7 @@
             return chart_data;
         }
 
-        function showStats () {
+        function showStats() {
             // CALLBACK : called when a button is selected
 
             // shows the focus on the correct button
@@ -44,24 +31,20 @@
             $(this).addClass("focus");
 
             // loads data and shows it
-            $.getJSON(this.stats_target_url, {format: 'json'}, displayStats);
+            $.getJSON(this.stats_target_url, displayStats);
         }
 
-        function displayStats (data) {
+        function displayStats(data) {
             // reads the json data and updates the chart display
 
             var chart_datasets = [];
-            var charts = dictToArray(data.charts);
-
             // are the points indexed by timestamps?
             var is_time_chart = data.is_time_chart || false;
 
             // reads the charts data
-            for (var i = 0; i < charts.length; i++) {
-                var chart = charts[i];
-
+            for (let chart of data.charts) {
                 // format the data
-                var chart_data =  is_time_chart ? handleTimeChart(chart.values) : dictToArray(chart.values, 0);
+                var chart_data = is_time_chart ? handleTimeChart(chart.values) : chart.values;
 
                 chart_datasets.push(
                     {
@@ -76,29 +59,24 @@
 
             // options for chartjs
             var chart_options =
-                {
-                    responsive: true,
-                    maintainAspectRatio: false,
-                    tooltips: {
-                        mode: 'index',
-                        intersect: false,
-                    },
-                    hover: {
-                        mode: 'nearest',
-                        intersect: false,
-                    }
-                };
+            {
+                responsive: true,
+                maintainAspectRatio: false,
+                tooltips: {
+                    mode: 'index',
+                    intersect: false,
+                },
+                hover: {
+                    mode: 'nearest',
+                    intersect: false,
+                }
+            };
 
             // additionnal options for time-indexed charts
             if (is_time_chart) {
                 chart_options['scales'] = {
                     xAxes: [{
                         type: "time",
-                        display: true,
-                        scaleLabel: {
-                            display: false,
-                            labelString: 'Date'
-                        },
                         time: {
                             tooltipFormat: 'll HH:mm',
                             displayFormats: {
@@ -115,26 +93,19 @@
                         }
 
                     }],
-                    yAxes: [{
-                        display: true,
-                        scaleLabel: {
-                            display: false,
-                            labelString: 'value'
-                        }
-                    }]
                 };
             }
 
             // global object for the options
             var chart_model =
-                {
-                    type: 'line',
-                    options: chart_options,
-                    data: {
-                        labels: data.labels || [],
-                        datasets: chart_datasets,
-                    }
-                };
+            {
+                type: 'line',
+                options: chart_options,
+                data: {
+                    labels: data.labels || [],
+                    datasets: chart_datasets,
+                }
+            };
 
             // saves the previous charts to be destroyed
             var prev_chart = content.children();
@@ -151,23 +122,26 @@
         }
 
         // initialize the interface
-        function initialize (data) {
+        function initialize(data) {
             // creates the bar with the buttons
             buttons = $("<ul>",
-                        {class: "nav stat-nav",
-                         "aria-label": "select-period"});
+                {
+                    class: "nav stat-nav",
+                    "aria-label": "select-period"
+                });
 
             var to_click;
-            var context = data.stats;
 
-            for (var i = 0; i < context.length; i++) {
+            for (let stat of data.stats) {
                 // creates the button
-                var btn_wrapper = $("<li>", {role:"presentation"});
+                var btn_wrapper = $("<li>", { role: "presentation" });
                 var btn = $("<a>",
-                            {class: "btn btn-nav",
-                             type: "button"})
-                    .text(context[i].label)
-                    .prop("stats_target_url", context[i].url)
+                    {
+                        class: "btn btn-nav",
+                        type: "button"
+                    })
+                    .text(stat.label)
+                    .prop("stats_target_url", stat.url)
                     .on("click", showStats);
 
                 // saves the default option to select
@@ -189,7 +163,7 @@
 
         // constructor
         (function () {
-            $.getJSON(url, {format: 'json'}, initialize);
+            $.getJSON(url, initialize);
         })();
     };
 })(jQuery);