Jquery does not work in rails

I have such a problem. There is a layout:

<nav class="navbar navbar-default" role="navigation"> <div class="container-fluid"> <div class="navbar-header"> <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1"> <span class="sr-only">Toggle navigation</span> <span class="icon-bar"></span> <span class="icon-bar"></span> <span class="icon-bar"></span> </button> <a class="navbar-brand" href="#">MyBooks</a> </div> <div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1"> <ul class="nav navbar-nav"> <li class="active"><%= link_to "Главная",root_url%></li> <li><%= link_to "Каталог",catalog_url%></li> </ul> </div> </div> 

There is a script:

 $(document).on('page:load',new function(){ $('li').click(new function(){ $('li').removeClass(); $(this).addClass('active'); });}); 

But it does not work because such an error occurs:

 ReferenceError: $ is not defined 

What could be the reason? Gem I installed in the application.js connected. On the application.html.erb page there is also a connection. Gemfile:

 source 'https://rubygems.org' git_source(:github) do |repo_name| repo_name = "#{repo_name}/#{repo_name}" unless repo_name.include?("/") "https://github.com/#{repo_name}.git" end # Bundle edge Rails instead: gem 'rails', github: 'rails/rails' gem 'rails', '5.1.5' gem 'bootstrap-sass' gem 'faker' # Use sqlite3 as the database for Active Record # Use Puma as the app server gem 'puma', '~> 3.7' gem 'will_paginate' gem 'bootstrap-will_paginate' # Use SCSS for stylesheets gem 'sass-rails', '~> 5.0' # Use Uglifier as compressor for JavaScript assets gem 'uglifier', '>= 1.3.0' # See https://github.com/rails/execjs#readme for more supported runtimes # gem 'therubyracer', platforms: :ruby # Use CoffeeScript for .coffee assets and views gem 'coffee-rails', '~> 4.2' # Turbolinks makes navigating your web application faster. Read more: https://github.com/turbolinks/turbolinks gem 'turbolinks', '~> 5' # Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder gem 'jbuilder', '~> 2.5' gem 'jquery-rails' gem 'sdoc', group: :doc # Use Redis adapter to run Action Cable in production # gem 'redis', '~> 4.0' # Use ActiveModel has_secure_password gem 'bcrypt' gem 'carrierwave' gem 'mini_magick' # Use Capistrano for deployment # gem 'capistrano-rails', group: :development group :development, :test do gem 'sqlite3' # Call 'byebug' anywhere in the code to stop execution and get a debugger console gem 'byebug', platforms: [:mri, :mingw, :x64_mingw] # Adds support for Capybara system testing and selenium driver gem 'capybara', '~> 2.13' gem 'selenium-webdriver' end group :test do gem 'minitest-reporters' gem 'mini_backtrace' gem 'guard-minitest' gem 'rails-controller-testing' end group :development do gem 'letter_opener' # Access an IRB console on exception pages or by using <%= console %> anywhere in the code. gem 'web-console', '>= 3.3.0' gem 'listen', '>= 3.0.5', '< 3.2' # Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring gem 'spring' gem 'spring-watcher-listen', '~> 2.0.0' end group :production do gem 'pg' gem 'rails_12factor' gem 'puma', '~> 3.7' gem 'fog-aws' end # Windows does not include zoneinfo files, so bundle the tzinfo-data gem gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby] 

application.js

 //= require jquery //= require jquery_ujs //= require bootstrap //= require turbolinks //= require_tree .