http://www.phaninder.com/posts/put-and-delete-can-they-be-used-as-html-form-methods/edit

expressJs_put_form.html

<form method="post" action="/posts">
  <input type="hidden" name="_method" value="put">
  <input type="text" name="title">
  <textarea name="content"></textarea>
  <input type="submit" value="Save">
</form>
  

makePutReq.js

function makePutReq( url ){
  var xhr = new XMLHttpRequest();
  
  xhr.open( 'PUT', url, false );
  xhr.setRequestHeader( 'Content-Type', 'text/plain' );
  xhr.send( null );
}

rails_put_req.erb

<%= link_to refresh_post_user_post_path(@user,@post), :method => :put%>