Improve TOTP auto-submit code

* Listen to "input" event only, don't need "keyup"
* Add form double-submit protection
* Rewrite in plain JS (the page no longer loads jQuery)

static/js/auto-submit.js

@@ -1,7 +1,15 @@
-$(function() {
-    $("input[data-auto-submit]").on("keyup input", function() {
-        if (this.validity.valid) {
+window.addEventListener("DOMContentLoaded", function(e) {
+    var validateAndSubmit = function() {
+        if (this.validity.valid && !this.dataset.submitted) {
+            // Make sure we only submit the form once
+            this.dataset.submitted = true;
             this.form.submit();
         }
+    }
+
+    // Hook up validateAndSubmit to all input elements with the
+    // "data-auto-submit" attribute
+    document.querySelectorAll("input[data-auto-submit]").forEach((input) => {
+        input.addEventListener("input", validateAndSubmit);
     });
-})
+});

templates/accounts/login_totp.html

@@ -20,6 +20,7 @@
             pattern="[0-9]{6}"
             title="6-digit code"
             placeholder="6-digit code"
+            data-auto-submit="1"
             class="form-control input-lg"
             required
             autofocus />
@@ -41,6 +42,8 @@
 </div>
 {% endblock %}
 
+{% block base_scripts %}{% endblock %}
+
 {% block scripts %}
 {% compress js %}
 <script src="{% static 'js/auto-submit.js' %}"></script>