Add a "Back" button the public subscription/message page.

On a successful form submission, error message etc., check if there's
browser history and render a button that takes the user back to
a meaningful origin from the dead-end message page.

Closes #527.

i18n/cs-cz.json

@@ -111,6 +111,7 @@
     "forms.title": "Formuláře",
     "globals.buttons.add": "Přidat",
     "globals.buttons.addNew": "Přidat nový",
+    "globals.buttons.back": "Back",
     "globals.buttons.cancel": "Zrušit",
     "globals.buttons.clone": "Klonovat",
     "globals.buttons.close": "Zavřít",

i18n/de.json

@@ -111,6 +111,7 @@
     "forms.title": "Formulare",
     "globals.buttons.add": "Hinzufügen",
     "globals.buttons.addNew": "Neu hinzufügen",
+    "globals.buttons.back": "Back",
     "globals.buttons.cancel": "Abbrechen",
     "globals.buttons.clone": "Duplizieren",
     "globals.buttons.close": "Schließen",

i18n/en.json

@@ -111,6 +111,7 @@
     "forms.title": "Forms",
     "globals.buttons.add": "Add",
     "globals.buttons.addNew": "Add new",
+    "globals.buttons.back": "Back",
     "globals.buttons.cancel": "Cancel",
     "globals.buttons.clone": "Clone",
     "globals.buttons.close": "Close",

i18n/es.json

@@ -111,6 +111,7 @@
     "forms.title": "Formularios",
     "globals.buttons.add": "Agregar",
     "globals.buttons.addNew": "Agregar nuevo",
+    "globals.buttons.back": "Back",
     "globals.buttons.cancel": "Cancelar",
     "globals.buttons.clone": "Clonar",
     "globals.buttons.close": "Cerrar",

i18n/fr.json

@@ -111,6 +111,7 @@
     "forms.title": "Formulaires",
     "globals.buttons.add": "Ajouter",
     "globals.buttons.addNew": "Ajouter",
+    "globals.buttons.back": "Back",
     "globals.buttons.cancel": "Annuler",
     "globals.buttons.clone": "Cloner",
     "globals.buttons.close": "Fermer",

i18n/it.json

@@ -111,6 +111,7 @@
     "forms.title": "Formulari",
     "globals.buttons.add": "Aggiungi",
     "globals.buttons.addNew": "Aggiungi nuovo",
+    "globals.buttons.back": "Back",
     "globals.buttons.cancel": "Annulla",
     "globals.buttons.clone": "Clona",
     "globals.buttons.close": "Chiudi",

i18n/ml.json

@@ -111,6 +111,7 @@
     "forms.title": "ഫോമുകൾ",
     "globals.buttons.add": "ചേർക്കുക",
     "globals.buttons.addNew": "പുതിയത് ചേർക്കുക",
+    "globals.buttons.back": "Back",
     "globals.buttons.cancel": "ഉപേക്ഷിക്കുക",
     "globals.buttons.clone": "ക്ലോൺ ചെയ്യുക",
     "globals.buttons.close": "അടയ്ക്കുക",

i18n/pl.json

@@ -111,6 +111,7 @@
     "forms.title": "Formularze",
     "globals.buttons.add": "Dodanj",
     "globals.buttons.addNew": "Dodaj nowe",
+    "globals.buttons.back": "Back",
     "globals.buttons.cancel": "Anuluj",
     "globals.buttons.clone": "Klonuj",
     "globals.buttons.close": "Zamknij",

i18n/pt-BR.json

@@ -111,6 +111,7 @@
     "forms.title": "Formulários",
     "globals.buttons.add": "Adicionar",
     "globals.buttons.addNew": "Adicionar novo",
+    "globals.buttons.back": "Back",
     "globals.buttons.cancel": "Cancelar",
     "globals.buttons.clone": "Clonar",
     "globals.buttons.close": "Fechar",

i18n/pt.json

@@ -111,6 +111,7 @@
     "forms.title": "Formulários",
     "globals.buttons.add": "Adicionar",
     "globals.buttons.addNew": "Adicionar novo",
+    "globals.buttons.back": "Back",
     "globals.buttons.cancel": "Cancelar",
     "globals.buttons.clone": "Duplicar",
     "globals.buttons.close": "Fechar",

i18n/ro.json

@@ -111,6 +111,7 @@
     "forms.title": "Formulare",
     "globals.buttons.add": "Adaugă",
     "globals.buttons.addNew": "Adaugă nou",
+    "globals.buttons.back": "Back",
     "globals.buttons.cancel": "Anulează",
     "globals.buttons.clone": "Clonează",
     "globals.buttons.close": "Închide",

i18n/ru.json

@@ -111,6 +111,7 @@
     "forms.title": "Формы",
     "globals.buttons.add": "Добавить",
     "globals.buttons.addNew": "Добавить",
+    "globals.buttons.back": "Back",
     "globals.buttons.cancel": "Отменить",
     "globals.buttons.clone": "Клонировать",
     "globals.buttons.close": "Закрыть",

i18n/tr.json

@@ -111,6 +111,7 @@
     "forms.title": "Formlar",
     "globals.buttons.add": "Ekle",
     "globals.buttons.addNew": "Ekle yeni",
+    "globals.buttons.back": "Back",
     "globals.buttons.cancel": "İptal",
     "globals.buttons.clone": "Klonla",
     "globals.buttons.close": "Kapat",

static/public/static/style.css

@@ -116,6 +116,10 @@ input[type="text"], input[type="email"], select {
     display: none;
   }
 
+#btn-back {
+  display: none;
+}
+
 footer.container {
   margin-top: 15px;
   text-align: center;

static/public/templates/message.html

@@ -6,5 +6,22 @@
         {{ .Data.Message }}
     </div>
 
+    <p>
+        <a href="" class="button" id="btn-back">{{ L.T "globals.buttons.back" }}</a>
+    </p>
+
+    <script>
+        (function() {
+            // If there's page history to go back to, show the back button.
+            if(history && history.length >= 2) {
+                var btn = document.getElementById("btn-back");
+                btn.style.display = 'inline-block';
+                btn.onclick = function(e) {
+                    history.go(history.length > 2 ? -2 : -1);
+                    e.preventDefault();
+                };
+            }
+        })();
+    </script>
     {{ template "footer" .}}
 {{ end }}