Rails remote form sends html instead of js

Question

I have a remote `form_for` in my Rails 4 app that is not requesting a JavaScript response. I am getting an UnknownFormat error when I click submit on the form. It is saying the parameters were: ``` {"utf8"=>"✓", "authenticity_token"=>"eAzS1lELwDL9Qt+fM2hAPlPmCxCgFPuAvl1QYWOIL3IBPdrnxn0woYYC+5uzGjyqH3lQxGxWGrYq/fnMrFNfnw==", "artist"=>{"name"=>"Joe"}, "commit"=>"Save Artist"} ``` My form code is: ``` = form_for(@artist, remote: true, authenticity_token: true) do |f| - if @artist.errors.any? #error_explanation %h2= "#{pluralize(@artist.errors.count, "error")} prohibited this artist from being saved:" %ul - @artist.errors.full_messages.each do |msg| %li= msg .field = f.label :name = f.text_field :name .actions = f.submit 'Save Artist' ``` I have a `create.js.erb` file, and my `create` method in my `ArtistsController` looks like: ``` def new @artist = Artist.new respond_to do |format| format.js end end def create @artist = Artist.new(artist_params) if @artist.save respond_to do |format| f…

Accepted Answer

Try adding the `format` param to the `form_for`. You're requesting an `html` response by default and your controller doesn't know how to answer that. Requesting a `js` response should fix it.

```
= form_for(@artist, format: :js, authenticity_token: true) do |f|
```

Rails remote form sends html instead of js

Solution

Problem