diff --git a/lib/videojs-resolution-switcher.js b/lib/videojs-resolution-switcher.js
index e57346f..7c04c4b 100644
--- a/lib/videojs-resolution-switcher.js
+++ b/lib/videojs-resolution-switcher.js
@@ -119,7 +119,7 @@
           this.el().appendChild(label);
         }else{
           var staticLabel = document.createElement('span');
-          staticLabel.classList.add('vjs-resolution-button-staticlabel');
+					videojs.addClass(staticLabel, 'vjs-resolution-button-staticlabel');
           this.el().appendChild(staticLabel);
         }
        },
@@ -163,8 +163,8 @@
           label = document.createElement('span'),
           groupedSrc = {};
 
-      label.classList.add('vjs-resolution-button-label');
-
+			videojs.addClass(label, 'vjs-resolution-button-label');
+			
       /**
        * Updates player sources or returns current source URL
        * @param   {Array}  [src] array of sources [{src: '', type: '', label: '', res: ''}]
@@ -183,7 +183,7 @@
         groupedSrc = bucketSources(src);
         var choosen = chooseSrc(groupedSrc, src);
         var menuButton = new ResolutionMenuButton(player, { sources: groupedSrc, initialySelectedLabel: choosen.label , initialySelectedRes: choosen.res , customSourcePicker: settings.customSourcePicker}, settings, label);
-        menuButton.el().classList.add('vjs-resolution-button');
+				videojs.addClass(menuButton.el(), 'vjs-resolution-button');
         player.controlBar.resolutionSwitcher = player.controlBar.el_.insertBefore(menuButton.el_, player.controlBar.getChild('fullscreenToggle').el_);
         player.controlBar.resolutionSwitcher.dispose = function(){
           this.parentNode.removeChild(this);