diff --git a/templates/main.js b/templates/main.js
index bd0a44c6..37a3ac5f 100755
--- a/templates/main.js
+++ b/templates/main.js
@@ -190,7 +190,7 @@ function changeStyle(styleName, link) {
 	var stylesheet_choices = JSON.parse(localStorage.board_stylesheets);
 	if (board_name && stylesheet_choices[board_name]) {
 		for (var styleName in styles) {
-			if (styleName == stylesheet_choices[board_name]) {
+			if (styleName && styleName == stylesheet_choices[board_name]) {
 				changeStyle(styleName);
 				break;
 			}
@@ -201,7 +201,7 @@ function changeStyle(styleName, link) {
 	{% raw %}
 	if (localStorage.stylesheet) {
 		for (var styleName in styles) {
-			if (styleName == localStorage.stylesheet) {
+			if (styleName && styleName == localStorage.stylesheet) {
 				changeStyle(styleName);
 				break;
 			}