search not working in partial - ruby-on-rails

Question

i have 2 search fields in 2 different views. they both search for establishments and are identical except for styling.
one is in welcome/index.html.erb and works great.
the other is in a partial called _nav.html.erb and is called from application.html.erb and does not work at all.
do i need to pass something into the _nav partial for it to process the search form properly?
welcome/index.html.erb
<div>
<%= form_tag(establishments_path, method: "get") do %>
<div class="form-group">
<%= text_field_tag :search, params[:search],
placeholder: "Enter the name of an eatery", class: "form-control" %>
<div class="actions"><%= submit_tag "Search", :name => nil, class: "btn btn-primary" %></div>
</div>
<% end %>
</div>
_nav.html.erb
<form class="navbar-form navbar-left" role="search">
<%= form_tag(establishments_path, method: "get") do %>
<div class="form-group">
<%= text_field_tag :search, params[:search],
placeholder: "Search", class: "form-control" %></div>
<%= submit_tag "Search", :name => nil, class: "btn btn-primary" %>
<% end %>
</form>
application.html.erb
<%= render 'layouts/nav' %>
EstablishmentsController/index
def index
if params[:search]
#establishments = Establishment.search(params[:search].downcase).order("created_at ASC")
else
#establishments = Establishment.all.limit(25)
end
end

Answer 1

Your form_tag is already wrapped in a form:
<form class="navbar-form navbar-left" role="search">
#^^^^ Here
<%= form_tag(establishments_path, method: "get") do %>
#^^^^ and here again
<div class="form-group">
<%= text_field_tag :search, params[:search],
placeholder: "Search", class: "form-control" %></div>
<%= submit_tag "Search", :name => nil, class: "btn btn-primary" %>
<% end %>
</form>
When you click on the submit tag, it submits the wrong form (the first one).
You should use it like this:
<%= form_tag(establishments_path, method: :get, class: 'navbar-form navbar-left', role: 'search') do %>
<div class="form-group">
<%= text_field_tag :search, params[:search], placeholder: "Search", class: "form-control" %></div>
<%= submit_tag "Search", :name => nil, class: "btn btn-primary" %>
<% end %>