JS not executed in browser, UJS not working!

[dzonekl]

Hi,

Rails: 4.0.8
jquery-rails (3.1.1)

I followed, troubleshooting here:

http://www.alfajango.com/blog/rails-js-erb-remote-response-not-executing/

I have a simple test, which returns the JS (I See it in the console).

    <div class="text-center">
        <%= link_to 'Invoke UJS!',{:action => :demo, :controller => :public}, :class => "btn btn-default btn-lg", :remote => true %>
    </div>
    <div id="demo">
        ...
    </div>

The console result is this, so Ajax call is executed nicely.

$("#demo").html("UJS Inserted!");

The JS executes, when pasting in the Firebug command panel, but not by itself.

What am I doing wrong? Does UJS actually work?

application.js

//= require jquery
//= require jquery_ujs

[rafaelfranca]

There are any error on the Rails console or in the Firebug console? How can we reproduce this problem?

[dzonekl]

No, no errors. Reproducing it, would mean I need to share the whole app.
This app was migrated from 2.x onwards, so perhaps some things aren't configured properly. I could post some of the config files or asset definitions? Please advise.

[dzonekl]

... Could this problem be related to caching? I still use Observers, action caching etc.. but not on this specific test.. I don't get it, this is on the browser, and the js looks correct, so which circumstances would cause the browser (Or ujs) not to execute the js? I have been reading [1], that it might be interpreted as text instead of js. But how do I debug this? Any hints on where to look in jquery_ujs? (Where to set a breakpoint?)

[1] http://stackoverflow.com/questions/13635548/format-js-is-not-manipulating-dom-once-action-caching-enabled

[dzonekl]

... what does this mean? (It's on the answer in the stack overflow issue in my previous comment).
Sorry for spamming!

" I found out what's wrong. jQuery actually surround the incoming script with a so that the browser evaluates the incoming code. But the caching mechansim merely saves the code as text and when one re-request, it returns the code as text but not evaluate it. Therefore, one needs to eval the code explicitly"

[dzonekl]

I guess, I could check the MIME type:

http://api.jquery.com/jquery.ajax/ (datatype section).

[dzonekl]

Aha, response MIME, is text/html, that's no good!

Cache-Control max-age=0, private, must-revalidate
Connection Keep-Alive
Content-Encoding gzip
Content-Length 54
Content-Type text/html; charset=utf-8
Date Fri, 15 Aug 2014 08:35:55 GMT
Etag "ebb20f41b2d35f7a33d95c2290ffd620"
Keep-Alive timeout=15, max=100
Server Apache/2.2.14 (Ubuntu)
Status 200 OK
Vary Accept-Encoding
X-Frame-Options SAMEORIGIN
X-Powered-By Phusion Passenger 4.0.42
X-Request-Id 525c899a-89f1-40bd-90a5-8fadc43647a5
X-Runtime 0.080784
X-Ua-Compatible chrome=1
X-XSS-Protection 1; mode=block
x-content-type-options nosniff

[dzonekl]

IS this correct?
'''

A demo action.

def demo
respond_to do |format|
format.html { render action: "demo" }
format.js {}
end
end
'''

[dzonekl]

Found it!
A filter, set the content-type. (Sorry for bugging, you, I have inherited this application, it's Instiki, a wiki system), so I don't know all the code.

This is what the filter does:

def set_content_type_header
response.charset = 'utf-8'
if %w(atom_with_content atom_with_headlines).include?(action_name)
response.content_type = Mime::ATOM
elsif %w(tex tex_list).include?(action_name)
response.content_type = Mime::TEXT
elsif xhtml_enabled?
if request.user_agent =~ /Validator/ or request.env.include?('HTTP_ACCEPT') &&
Mime::Type.parse(request.env["HTTP_ACCEPT"]).include?(Mime::XHTML)
response.content_type = Mime::XHTML
elsif request.user_agent =~ /MathPlayer/
response.charset = nil
response.content_type = Mime::XHTML
response.extend(MathPlayerHack)
else
response.content_type = Mime::HTML
end
else
response.content_type = Mime::HTML
end
end