fix: some minor improvements

app/templates/layout/layout.html

@@ -31,11 +31,11 @@
           </div>
           {% if not session["id"] %}
           <div class="col-md-2 d-none d-lg-flex align-items-center justify-content-center">
-            <a type="button" class="btn btn-primary w-75" href="{{ROUTES['users']['login']}}" >Log In</a>
+            <a class="btn btn-primary w-75" href="{{ROUTES['users']['login']}}" >Log In</a>
           </div>
           {% else %}
           <div class="col-md-2 d-none d-lg-flex align-items-center justify-content-center">
-            <a type="button" class="btn btn-danger w-75" href="{{ROUTES['users']['logout']}}" >Log Out</a>
+            <a class="btn btn-danger w-75" href="{{ROUTES['users']['logout']}}" >Log Out</a>
           </div>
           {% endif %}
         </div>
@@ -52,6 +52,23 @@
         {% block footer %} 
         &copy; Copyright 2010 by <a href="http://domain.invalid/">you</a>. 
         {% endblock %}
+        <form action="https://validator.w3.org/check" class="text-center" enctype="multipart/form-data" method="post" target="_blank">
+            <input name="doctype" type="hidden" value="HTML5">
+            <input name="fragment" type="hidden">
+            <input alt="Validate" src="/static/I_heart_validator.png" type="image"> <!-- https://validator.w3.org/ -->
+        </form>
+        <script>
+            document.addEventListener('DOMContentLoaded', function() {
+                // Adapted from https://stackoverflow.com/a/10162353
+                const html = '<!DOCTYPE ' +
+                document.doctype.name +
+                (document.doctype.publicId ? ' PUBLIC "' + document.doctype.publicId + '"' : '') +
+                (!document.doctype.publicId && document.doctype.systemId ? ' SYSTEM' : '') +
+                (document.doctype.systemId ? ' "' + document.doctype.systemId + '"' : '') +
+                '>\n' + document.documentElement.outerHTML;
+                document.querySelector('form[action="https://validator.w3.org/check"] > input[name="fragment"]').value = html;
+            });
+        </script>
       </footer>
 
   </body>