--- a/dom/animation/test/css-animations/file_event-dispatch.html
+++ b/dom/animation/test/css-animations/file_event-dispatch.html
@@ -37,17 +37,17 @@ function AnimationEventHandler(target) {
 AnimationEventHandler.prototype.clear = () => {
   this.animationstart     = undefined;
   this.animationiteration = undefined;
   this.animationend       = undefined;
   this.animationcancel    = undefined;
 }
 
 function setupAnimation(t, animationStyle) {
-  var div = addDiv(t, { style: "animation: " + animationStyle });
+  var div = addDiv(t, { style: 'animation: ' + animationStyle });
   var watcher = new EventWatcher(t, div, [ 'animationstart',
                                            'animationiteration',
                                            'animationend',
                                            'animationcancel' ]);
   var animation = div.getAnimations()[0];
 
   return [animation, watcher, div];
 }