catch for external cards accessed internally

.ci/.autoRedirect

@@ -27,8 +27,18 @@
 
         if(status === 200){
             // internal pages
-            if (sub.length > 0) { sub = 'internal/'+sub; }
-            window.location.href = 'https://r3-core.pages.uni.lu/howto-cards-internal/stable/'+sub;
+            if (sub.length > 0) {
+                UrlExists('https://r3-core.pages.uni.lu/howto-cards-internal/stable/internal/'+sub, function(status){
+                // redirect if card is actually internal and exists
+                if (status == 200) {
+                    window.location.href = 'https://r3-core.pages.uni.lu/howto-cards-internal/stable/internal/'+sub;
+                } else {
+                    window.location.href = 'https://r3-core.pages.uni.lu/howto-cards-internal/stable/external/'+sub;
+                }
+            } else {
+                window.location.href = 'https://r3-core.pages.uni.lu/howto-cards-internal/stable/'+sub;
+            }
+
         } else {
             // external pages
             if (sub.length > 0) { sub = 'external/'+sub; }