Rails Ajax表单语法错误

What is the difference in below 2 Rails ajax forms.

Form 1

<%= form_tag '/posts', remote: true do %>

<% end -%>

Form 2

<%= form_tag ('/posts', remote: true) do %>

<% end -%>

While Form 1 works without any problem the form with parenthesis (Form 2) cause the below syntax error when trying to view the page in browser.

/home/my_app/app/views/articles/new.html.erb:3: syntax error, unexpected ',', expecting ')'
...er.append=  form_tag ('/posts', remote: true) do @output_buf...
...                               ^
/home/my_app/app/views/articles/new.html.erb:8: syntax error, unexpected keyword_ensure, expecting end-of-input

I am using Rails 4.0.1.

yes, i also suffered this problem. For some reason removing the space after form_for method worked for me. So, this both will work.

 <%= form_tag('/posts', remote: true) do %>

and

 <%= form_tag '/posts', remote: true do %>