ActionController::UnknownFormat with format.js for ajax implementation (Rail 4)

Question

i try to use Ajax in my application with Rails 4. To send my js to the client i use :

   respond_to do |format|
        format.js 
   end

Answer 1

HTML

Looks like the problem is you're sending an HTML request for whatever reason:

Oweb::MainController#setmagasinstatus as HTML

I'd surmise the "unkown format" error will therefore be caused by your lack of definition for the html mime-type in your action. I'd imagine this would work to resolve the error at surface-level:

 respond_to do |format|
     format.js 
     format.html
  end

---

Ajax

If the above is correct, the question then turns to "why is an HTML mime-type being sent?"

Due to not being able to see your actual Ajax code, I'd recommend the problem will either be that you're just sending a standard HTTP request (ajax is XHR); or you'll have an issue with the declaration with the ajax request

You must remember that Ajax (Asynchronous Javascript And XML) is meant to send a request on your behalf -- like a pseudo browser. This means if you want to send an ajax request, it has to be done through Javascript (hence the format.js mime type handler)

--

Personally, I think you're not sending an ajax request, although it could also be that you're sending a different dataType, such as JSON