diff --git a/src/game/result/result.js b/src/game/result/result.js
index 4e1cd1b..dec18cb 100644
--- a/src/game/result/result.js
+++ b/src/game/result/result.js
@@ -33,7 +33,7 @@ var Result = {
 
 		// top ui
 		var screenTopUI = new ScreenTopUI();
-		screenTopUI.makeBackButton( function() { (function() { this.back(); }).bind(this) });
+		screenTopUI.makeBackButton( (function() { this.back(); }).bind(this) );
 		screenTopUI.makeFullScreenButton();
 
 
diff --git a/src/game/start/start.js b/src/game/start/start.js
index 05e2c7f..b675a17 100644
--- a/src/game/start/start.js
+++ b/src/game/start/start.js
@@ -29,7 +29,7 @@ var Start = {
 
 		// top ui
 		var screenTopUI = new ScreenTopUI();
-		screenTopUI.makeBackButton( function() { (function() { this.back(); }).bind(this) });
+		screenTopUI.makeBackButton( (function() { this.back(); }).bind(this) );
 		screenTopUI.makeFullScreenButton();