diff --git a/cinera/cinera_pre.js b/cinera/cinera_pre.js
index bdbf988..60b12ec 100644
--- a/cinera/cinera_pre.js
+++ b/cinera/cinera_pre.js
@@ -226,7 +226,7 @@ function GetRule(SelectorText)
     for(var StyleSheetIndex = StyleSheets.length - 1; StyleSheetIndex >= 0; --StyleSheetIndex)
     {
         var ThisSheet = StyleSheets[StyleSheetIndex];
-        if(ThisSheet.href.includes(location.hostname))
+        if(ThisSheet.href !== null && ThisSheet.href.includes(location.hostname))
         {
             var Rules = ThisSheet[cssRuleCode];
             for(var RuleIndex = Rules.length - 1; RuleIndex >= 0; --RuleIndex)
@@ -267,7 +267,7 @@ GetLocalStyleSheet()
     for(var StyleSheetIndex = StyleSheets.length - 1; StyleSheetIndex >= 0; --StyleSheetIndex)
     {
         var This = StyleSheets[StyleSheetIndex];
-        if(This.href.includes(location.hostname) && !This.disabled)
+        if(This.href !== null && This.href.includes(location.hostname) && !This.disabled)
         {
             Result = This;
             break;