How do I stop a remote form from submitting?

Question

I have a form that can be used both remotely and normally.

= form_for @comment, html: { class: 'comment-form' }, remote: request.xhr? do |f|
  = f.text_area :body
  = f.submit

I want the form to submit only if the body textarea has content:

  $(document).on 'submit', '.comment-form', (e) ->
    text = $(this).find('#comment_body').val()
    false if text.length < 1

That code works when the form is not Ajax. But when it's remote, it fails and the form still submits. Why? I also tried:

if text.length < 1
  e.preventDefault()
  false

I'm using Rails 4 with Turbolinks.

Update: I tried binding the ajax:beforeSend event, it still submits:

  $(document).on 'page:load', '.comment-form', ->
    $(this).bind 'ajax:beforeSend', ->
      alert "hi"

I see no alert...

Answer 1

You could potentially implement a handler for the ajax:beforeSend event to prevent your form from being submitted. It looks like the submit stops if your event handler returns false.

Wiki: https://github.com/rails/jquery-ujs/wiki/ajax

Example implementation: Stop $.ajax on beforeSend