Merge pull request #18958 from andreynering/guides-form-remote

Improving remote forms guides [ci skip]

guides/source/working_with_javascript_in_rails.md

@@ -191,6 +191,34 @@ $(document).ready ->
 Obviously, you'll want to be a bit more sophisticated than that, but it's a
 start. You can see more about the events [in the jquery-ujs wiki](https://github.com/rails/jquery-ujs/wiki/ajax).
 
+Another possibility is returning javascript directly from the server side on
+remote calls:
+
+```ruby
+# articles_controller
+def create
+  respond_to do |format|
+    if @article.save
+      format.html { ... }
+      format.js do
+        render js: <<-endjs
+          alert('Article saved successfully!');
+          window.location = '#{article_path(@article)}';
+        endjs
+      end
+    else
+      format.html { ... }
+      format.js do
+        render js: "alert('There are empty fields in the form!');"
+      end
+    end
+  end
+end
+```
+
+NOTE: If javascript is disabled in the user browser, `format.html { ... }`
+block should be executed as fallback.
+
 ### form_tag
 
 [`form_tag`](http://api.rubyonrails.org/classes/ActionView/Helpers/FormTagHelper.html#method-i-form_tag)