Last Updated: February 03, 2018
· edokun_
Pencil sketch

Open a rails form with Twitter Bootstrap modals

Sometimes we require to open a form or display information that opens up as modal windows, I will show you an easy way to do it using twitter bootstrap modals.

First make sure you added the bootstrap-sass gem to your gemfile and also used bundle to install the gem.

Also in your application.js include the calling to the bootstrap-modal javascript file in the following way:

//= require bootstrap-modal

Now in the routes.rb file add the route to the partial you want to show as modal, for example:

get "project/new_release" => 'project#new_release', :as => :new_release

In the controller add the respond_to block to use some ajax magic

def new_release
  respond_to do |format|

In the calling view use a link_to helper in the following way:

<%= link_to 'Add release', new_release_path,  {:remote => true, 'data-toggle' =>  "modal", 'data-target' => '#modal-window'}  %>

We need to have a DIV in the calling view that will load the partial as the modal window, so we are having something like this:

<div id="modal-window" class="modal hide fade" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true"></div>

We are going to put the partial form inside that div with jquery.

Make sure to have the partial, in this case should be a file named _new_release.html.erb, inside this you will have the content you want to show for example:

<div class="modal-header">
   <button type="button" class="close" data-dismiss="modal" aria-hidden="true">×</button>
   <h3 id="myModalLabel">Modal header</h3>
 <div class="modal-body">
   **here comes whatever you want to show!**
 <div class="modal-footer">
   <button class="btn" data-dismiss="modal" aria-hidden="true">Close</button>
   <button class="btn btn-primary">Save changes</button>

Now we need some javascript to make this works, make a file named same way as the controller action but with the suffix .js.erb for this example should be:


And inside the file add the following:

$("#modal-window").html("<%= escape_javascript(render 'project/new_release') %>");

That's it, now when you click on the link a nice modal will show up with a very clean fade effect.

Hope this little snippet can be handy for you.
I took all the information from the following sites.

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19 Responses
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Thank you. We still need to add $("modal-window).modal() in the .js.erb file for the modal to trigger.

over 1 year ago ·
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great, Thanks.

over 1 year ago ·

'data_toggle' should be 'data-toggle'

over 1 year ago ·
Pencil sketch

Thanks, for the advice, I will correct it.

over 1 year ago ·

@gautham-nookala No, you don't. It get's triggered in the link_to statement with data-target and data-toogle. See the official Bootstrap manual.

To get it working with Bootstrap 3 you have to remove all "hide" class references in your < div >

over 1 year ago ·
Default profile 4 normal

this is just what i find ,
thank you very much

over 1 year ago ·

got it work after having removed "hide" from the class

over 1 year ago ·
Image normal

hi , I have tried this one , i got fade screen but no popup was displaying

over 1 year ago ·

How to handle with multiple modals?
I have now this:
$('.modal-service').empty().html('<%= escapejavascript(render :partial => 'serviceform', :object => @service) %>');
$('.modal-employee').empty().html('<%= escapejavascript(render :partial => 'addemployee', :object => @service) %>');

But with every click to open a modal, it loads all the modals which causing some conflicts.

over 1 year ago ·

I got everything to work without using the new_release.js.erb file as well as the 'require' in application.js. Why would you need that in there exactly? Great tutorial btw!

over 1 year ago ·


over 1 year ago ·

I'm really stuck in trying to get this setup.

For Rails 4 users, one thing to note is that the require bootstrap/modal needs to be / instead of -.

Also, see this post. The suggestion was to add $('#modal-window').modal('show'); to the end of the js file and to keep the js.erb file in the views folder instead of the app assets javascripts folder, so that the render action can work.

I still can't get this working though. When I click the link that is supposed to render the modal, I get a greyed out screen but no modal. No console errors and html inspector shows modal container is recognised. The network inspector does not show any path as available.

over 1 year ago ·
over 1 year ago ·

@endlessly stuck - I had better luck looking at this: http://v4-alpha.getbootstrap.com/components/modal/
bootstrap was already included in my (rails 5) project so those methods were already available. I just added this to my button code: {:remote => true, 'data-toggle' => "modal", :class => 'btn btn-primary btn-small', 'data-target' => '#myModal'}. The :remote => true asks the controller for js - so the controller respond_to stuff above is important. (as well as the routes.rb part). Then your js code for the partial above should also work.

over 1 year ago ·

@endlessly I had the same problem as you, I fixed it this way:
1. Your calling to render the modal must be outside <body>, <nav> or any tag, for example mine:
<%= linkto 'Sign up', signin_path, {:remote => true, 'data-toggle' => "modal", :class => 'nav-item nav-link', 'data-target' => '#modal-window'} %>

<div id="modal-window" class="modal" tabindex="-1" role="dialog" aria-labelledby="gridModalLabel" aria-hidden="true">

over 1 year ago ·

@endlessly stuck try $("#modal-window").html("<%= j escapejavascript(render 'project/newrelease') %>");

over 1 year ago ·

@endlessly stuck, a buddy of mine doing frontend have just show me the trick that made it working (I was stuck too with greyed out screen but no modal):

The modal window should be declared like this:

<div id="modal-window" class="modal hide fade" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true">
  <div class="modal-dialog" role="document">
    <div class="modal-content"></div>

Then, rendering should be made this way:

$("#modal-window").find(".modal-content").html("<%= j (render 'application/modal') %>");
over 1 year ago ·

Thanks for the important information.

4 months ago ·

Thank you so much. You're a life-saver. @texpert, thanks for the useful info. OP, you should add @texpert's info to your article to keep up-to-date.

4 months ago ·