[1]Minor UI Change;[2]Refine logic adding new ID

templates/admin.html

@@ -9,6 +9,12 @@
       </div>
     {% endif %}
 
+    {% if id_is_invalid %}
+      <div class="text-danger">
+        <strong>Warning!</strong> The account name is invalid.
+      </div>
+    {% endif %}
+
     <div class = "container">
       <div class="row">