Fix: error message for IE

Author: mysticatea

src/index.html

@@ -160,12 +160,15 @@
         })
 
         // Show loading error.
-        function onLoadError() {
-            MainContent.innerHTML = "Failed to load. Please ensure you are using the browser which supports ES2015."
+        window.onerror = function onLoadError() {
+            MainContent.innerHTML = "Failed to load. Please ensure you are using a browser which supports ES2015."
             MainContent.show()
         }
     </script>
-    <script src="index.js" async onerror="onLoadError"></script>
+    <script src="index.js"></script>
+    <script>
+        window.onerror = null
+    </script>
 </body>
 
 </html>