編集時にページ遷移を確認

app/views/posts/_form.html.erb

@@ -32,7 +32,7 @@
 
 
     <div class="col-md-2">
     <div class="col-md-2">
       <div class="actions">
       <div class="actions">
-        <%= f.submit class: 'btn btn-primary' %>
+        <%= f.submit class: 'btn btn-primary', id: 'save_button' %>
       </div>
       </div>
     </div>
     </div>
 
 
@@ -71,6 +71,14 @@
   $(function(){
   $(function(){
     'use strict';
     'use strict';
 
 
+    var confirmUnload = function() {
+      return '前のページに戻りますか？';
+    };
+    $(window).on('beforeunload', confirmUnload);
+    $('#save_button').on('click', function(){
+      $(window).off('beforeunload', confirmUnload);
+    });
+
     // Automaticaly change textarea height.
     // Automaticaly change textarea height.
     $('textarea.autosize').autosize();
     $('textarea.autosize').autosize();