diff --git a/accountant/frontend/static/js/accounts.js b/accountant/frontend/static/js/accounts.js
index 5e63943..f6c695e 100644
--- a/accountant/frontend/static/js/accounts.js
+++ b/accountant/frontend/static/js/accounts.js
@@ -19,25 +19,36 @@
 
 accountantApp
 
-.factory("Account", ["$resource", function($resource) {
+.factory('Account', ['$resource', function($resource) {
     var Account = $resource(
-        "/api/account/:id", {
-            id: "@id"
+        '/api/account/:id', {
+            id: '@id'
         }
     );
 
     Account.prototype.getSolds = function() {
-        var Solds = $resource("/api/account/:id/solds", {id: this.id});
+        var Solds = $resource('/api/account/:id/solds', {id: this.id});
 
         this.solds = Solds.get();
     };
 
+    Account.prototype.getBalance = function(begin, end) {
+        var Balance = $resource(
+            '/api/account/:id/balance', {
+                id: this.id,
+                begin: begin.format('YYYY-MM-DD'),
+                end: end.format('YYYY-MM-DD')
+            });
+
+        this.balance = Balance.get();
+    };
+
     return Account;
 }])
 
 .controller(
-    "AccountController", [
-        "$scope", "Account", "Notification",
+    'AccountController', [
+        '$scope', 'Account', 'Notification',
         function($scope, Account, Notification) {
 
     /*
@@ -50,9 +61,9 @@ accountantApp
       }
 
       if(account.current <account.authorized_overdraft) {
-        return "danger";
+        return 'danger';
       } else if(account.current < 0) {
-        return "warning";
+        return 'warning';
       }
     };
 
@@ -65,9 +76,9 @@ accountantApp
         }
 
         if(value < account.authorized_overdraft) {
-            return "text-danger";
+            return 'text-danger';
         } else if(value < 0) {
-            return "text-warning";
+            return 'text-warning';
         }
     };
 
@@ -123,7 +134,7 @@ accountantApp
           return 0;
         });
 
-        Notification.success("Account #" + data.id + " saved.");
+        Notification.success('Account #' + data.id + ' saved.');
 
         return data;
       });
@@ -136,11 +147,11 @@ accountantApp
       var id = account.id;
 
       bootbox.confirm(
-        "Voulez-vous supprimer le compte \"" + account.name + "\" ?",
+        'Voulez-vous supprimer le compte \\\'' + account.name + '\\\' ?',
         function(result) {
           if(result) {
             account.$delete().then(function() {
-              Notification.success("Account #" + id + " deleted.");
+              Notification.success('Account #' + id + ' deleted.');
 
               // Remove account from array.
               $scope.accounts.splice($index, 1);
diff --git a/accountant/frontend/static/js/operations.js b/accountant/frontend/static/js/operations.js
index 4ba0213..50906ca 100644
--- a/accountant/frontend/static/js/operations.js
+++ b/accountant/frontend/static/js/operations.js
@@ -19,36 +19,36 @@
 
 accountantApp
 
-.factory("Operation", [ "$resource", function($resource)  {
+.factory('Operation', [ '$resource', function($resource)  {
     return $resource(
-        "/api/operation/:id", {
-            id: "@id"
+        '/api/operation/:id', {
+            id: '@id'
         }
     );
 }])
 
-.factory("OHLC", [ "$resource", "$routeParams",
+.factory('OHLC', [ '$resource', '$routeParams',
          function($resource, $routeParams)  {
     return $resource(
-        "/api/account/:account_id/ohlc", {
+        '/api/account/:account_id/ohlc', {
             account_id: $routeParams.accountId
         }
     );
 }])
 
-.factory("Category", [ "$resource", "$routeParams",
+.factory('Category', [ '$resource', '$routeParams',
          function($resource, $routeParams)  {
     return $resource(
-        "/api/account/:account_id/category", {
+        '/api/account/:account_id/category', {
             account_id: $routeParams.accountId
         }
     );
 }])
 
-.factory("Balance", [ "$resource", "$routeParams",
+.factory('Balance', [ '$resource', '$routeParams',
          function($resource, $routeParams)  {
     return $resource(
-        "/api/account/:account_id/balance", {
+        '/api/account/:account_id/balance', {
             account_id: $routeParams.accountId
         }
     );
@@ -58,8 +58,8 @@ accountantApp
  * Controller for category chart.
  */
 .controller(
-  "CategoryChartController", [
-    "$rootScope", "$scope", "$http", "Category", "Balance",
+  'CategoryChartController', [
+    '$rootScope', '$scope', '$http', 'Category', 'Balance',
     function($rootScope, $scope, $http, Category, Balance) {
 
   var colors = Highcharts.getOptions().colors;
@@ -90,14 +90,14 @@ accountantApp
     },
     yAxis: {
       title: {
-        text: "Categories"
+        text: 'Categories'
       }
     },
     title: {
-      text: "Répartition dépenses/recettes"
+      text: 'Répartition dépenses/recettes'
     },
     series: [{
-      name: "Value",
+      name: 'Value',
       data: [],
       innerSize: '33%',
       size: '60%',
@@ -108,7 +108,7 @@ accountantApp
         distance: -40
       }
     }, {
-      name: "Value",
+      name: 'Value',
       data: [],
       innerSize: '66%',
       size: '60%',
@@ -165,20 +165,20 @@ accountantApp
    */
   $scope.getBalance = function(begin, end) {
     Balance.get({
-      begin: begin.format("YYYY-MM-DD"),
-      end: end.format("YYYY-MM-DD")
+      begin: begin.format('YYYY-MM-DD'),
+      end: end.format('YYYY-MM-DD')
     }, function(balance) {
       // Update pie chart subtitle with Balance.
       $scope.config.subtitle = {
-        text: "Balance: " + balance.balance
+        text: 'Balance: ' + balance.balance
       };
 
       $scope.config.series[0].data = [{
-        name: "Revenues",
+        name: 'Revenues',
         y: balance.revenues,
         color: $scope.revenueColor
       }, {
-        name: "Expenses",
+        name: 'Expenses',
         y: -balance.expenses,
         color: $scope.expenseColor,
       }];
@@ -186,7 +186,7 @@ accountantApp
   };
 
   // Reload categories and account status on range selection.
-  $rootScope.$on("rangeSelectedEvent", function(e, args) {
+  $rootScope.$on('rangeSelectedEvent', function(e, args) {
     $scope.load(args.begin, args.end);
     $scope.getBalance(args.begin, args.end);
   });
@@ -196,8 +196,8 @@ accountantApp
  * Controller for the sold chart.
  */
 .controller(
-  "SoldChartController", [
-    "$rootScope", "$scope", "$http", "OHLC",
+  'SoldChartController', [
+    '$rootScope', '$scope', '$http', 'OHLC',
     function($rootScope, $scope, $http, OHLC) {
   // Configure chart for operations.
   $scope.config = {
@@ -209,22 +209,22 @@ accountantApp
         buttons: [{
           type: 'month',
           count: 1,
-          text: "1m"
+          text: '1m'
         }, {
-          type: "month",
+          type: 'month',
           count: 3,
-          text: "3m"
+          text: '3m'
         }, {
-          type: "month",
+          type: 'month',
           count: 6,
-          text: "6m"
+          text: '6m'
         }, {
-          type: "year",
+          type: 'year',
           count: 1,
-          text: "1y"
+          text: '1y'
         }, {
-          type: "all",
-          text: "All"
+          type: 'all',
+          text: 'All'
         }],
         selected: 0,
       },
@@ -242,8 +242,8 @@ accountantApp
       }
     },
     series: [{
-      type: "ohlc",
-      name: "Sold",
+      type: 'ohlc',
+      name: 'Sold',
       data: [],
       dataGrouping : {
         units : [[
@@ -256,18 +256,18 @@ accountantApp
       }
     }],
     title: {
-      text: "Sold evolution"
+      text: 'Sold evolution'
     },
     xAxis: {
-      type: "datetime",
+      type: 'datetime',
       dateTimeLabelFormats: {
-        month: "%e. %b",
-        year: "%Y"
+        month: '%e. %b',
+        year: '%Y'
       },
       minRange: 3600 * 1000 * 24 * 14, // 2 weeks
       events: {
         afterSetExtremes: function(e) {
-          $scope.$emit("rangeSelectedEvent", {
+          $scope.$emit('rangeSelectedEvent', {
             begin: moment.utc(e.min), end: moment.utc(e.max)
           });
         }
@@ -277,11 +277,11 @@ accountantApp
     },
     yAxis: {
       plotLines: [{
-        color: "orange",
+        color: 'orange',
         width: 2,
         value: 0.0
       }, {
-        color: "red",
+        color: 'red',
         width: 2,
         value: 0.0
       }]
@@ -302,7 +302,7 @@ accountantApp
         ]);
       });
 
-      $scope.$emit("rangeSelectedEvent", {
+      $scope.$emit('rangeSelectedEvent', {
         begin: $scope.config.xAxis.currentMin,
         end: $scope.config.xAxis.currentMax
       });
@@ -312,17 +312,17 @@ accountantApp
   };
 
   // Reload solds when an operation is saved.
-  $rootScope.$on("operationSavedEvent", function(e, operation) {
+  $rootScope.$on('operationSavedEvent', function(e, operation) {
     $scope.loadSolds();
   });
 
   // Reload solds when an operation is deleted.
-  $rootScope.$on("operationDeletedEvent", function(e, operation) {
+  $rootScope.$on('operationDeletedEvent', function(e, operation) {
     $scope.loadSolds();
   });
 
   // Update authorized overdraft on account loading.
-  $rootScope.$on("accountLoadedEvent", function(e, account) {
+  $rootScope.$on('accountLoadedEvent', function(e, account) {
     $scope.config.yAxis.plotLines[1].value = account.authorized_overdraft;
   });
 
@@ -334,8 +334,8 @@ accountantApp
  * Controller for the operations.
  */
 .controller(
-    "OperationController", [
-        "$scope", "$rootScope", "$routeParams", "Notification", "Account", "Operation",
+    'OperationController', [
+        '$scope', '$rootScope', '$routeParams', 'Notification', 'Account', 'Operation',
         function($scope, $rootScope, $routeParams, Notification, Account, Operation) {
   // List of operations.
   $scope.operations = [];
@@ -411,9 +411,9 @@ accountantApp
     operation.confirmed = true;
 
     return operation.$save().then(function(data) {
-      Notification.success("Operation #" + data.id + " saved.");
+      Notification.success('Operation #' + data.id + ' saved.');
 
-      $scope.$emit("operationSavedEvent", data);
+      $scope.$emit('operationSavedEvent', data);
     });
   };
 
@@ -424,16 +424,16 @@ accountantApp
     var id = operation.id;
 
     bootbox.confirm(
-      "Voulez-vous supprimer l'opération \"" + operation.label + "\" ?",
+      'Voulez-vous supprimer l\'opération \\\'' + operation.label + '\\\' ?',
       function(result) {
         if(result) {
           operation.$delete().then(function() {
-            Notification.success("Operation #" + id + " deleted.");
+            Notification.success('Operation #' + id + ' deleted.');
 
             // Remove operation from array.
             $scope.operation.splice($index, 1);
 
-            $scope.$emit("operationDeletedEvent", operation);
+            $scope.$emit('operationDeletedEvent', operation);
           });
         }
       }
@@ -447,7 +447,7 @@ accountantApp
   /*
    * Reload operations on rangeSelectedEvent.
    */
-  $rootScope.$on("rangeSelectedEvent", function(e, args) {
+  $rootScope.$on('rangeSelectedEvent', function(e, args) {
     $scope.load(args.begin, args.end);
   });
 }]);
diff --git a/accountant/frontend/static/js/scheduler.js b/accountant/frontend/static/js/scheduler.js
index 1bb544e..4f5e971 100644
--- a/accountant/frontend/static/js/scheduler.js
+++ b/accountant/frontend/static/js/scheduler.js
@@ -18,17 +18,17 @@
 
 accountantApp
 
-.factory("ScheduledOperation", ["$resource", function($resource) {
+.factory('ScheduledOperation', ['$resource', function($resource) {
     return $resource(
-        "/api/scheduled_operation/:id", {
-            id: "@id"
+        '/api/scheduled_operation/:id', {
+            id: '@id'
         }
     );
 }])
 
 .controller(
-    "SchedulerController", [
-        "$scope", "$rootScope", "$routeParams", "Notification", "ScheduledOperation",
+    'SchedulerController', [
+        '$scope', '$rootScope', '$routeParams', 'Notification', 'ScheduledOperation',
         function($scope, $rootScope, $routeParams, Notification, ScheduledOperation) {
     // Operation store.
     $scope.operations = [];
@@ -68,7 +68,7 @@ accountantApp
       }
 
       return operation.$save().then(function(data) {
-        Notification.success("Operation #" + data.id + " saved.");
+        Notification.success('Operation #' + data.id + ' saved.');
       });
     };
 
@@ -90,11 +90,11 @@ accountantApp
       var id = operation.id;
 
       bootbox.confirm(
-        "Voulez-vous supprimer l'operation planifiée \"" + operation.label + "\" ?",
+        'Voulez-vous supprimer l\'operation planifiée \\\'' + operation.label + '\\\' ?',
         function(result) {
           if(result) {
             operation.$delete().then(function() {
-              Notification.success("Operation #" + id + " deleted.");
+              Notification.success('Operation #' + id + ' deleted.');
 
               // Remove account from array.
               $scope.operations.splice($index, 1);