With Rails UJS, how to submit a remote form from a function

Question

I'm using Rails UJS. I have a form setup to do a remote submit like so:

<form accept-charset="UTF-8" action="/subscriptions" class="new_subscription form-horizontal" id="new_subscription" data-remote="true" data-type="json" method="POST">

I'm trying to find a way to submit this form from a JavaScript function. I've tried:

var form$ = $("#new_subscription");
form$.get(0).submit();

but the problem with this is that it submits the form w/o the remote, it posts to the server and refreshes the page. Any idea why that is? Is there a different way to submit a remote form?

Thanks

Answer 1

Perhaps for those using jquery-ujs (Rails 5.0 default and below), as Mikhail as already answered, triggering the custom jquery event will work, i.e.:

$("#new_subscription").trigger("submit.rails");

For those who have stumbled upon this question in 2017 and is using Rails 5.1, the answer will be different. Rails 5.1 has dropped jquery as a dependency and therefore has replaced jquery-ujs with a complete rewritten rails-ujs. See: http://weblog.rubyonrails.org/2017/4/27/Rails-5-1-final/

As such, you'll have to trigger the proper CustomEvent object in rails-ujs:

As of the moment, there's no published/recommended way of doing it in the documentation (a.k.a. RailsGuides), but here are a number of options that you could use just by looking at Rails' source code:

1. Use Rails.fire function:

   nativeFormEl = $("#new_subscription")[0] // you need the native DOM element
   Rails.fire(nativeFormEl, 'submit')
   

2. You could also programmatically call the Rails.handleRemote handler (the one that actually submits forms with data-remote=true via XHR:

   nativeFormEl = $("#new_subscription")[0] // you need the native DOM element
   Rails.handleRemote.call(nativeFormEl, event); // unfortunately, you cannot reference the previously created submit CustomEvent object by rails-ujs.js
   //  ... or ...
   Rails.handleRemote.call(nativeFormEl) // submits via XHR successfully, but throws an error after success callback at Rails.stopPropagation
   

I prefer Option 1 because it's just a wrapper that uses more recent Web API methods i.e. creating a CustomEvent and dispatches it to the EventTarget via dispatchEvent.