Ruby on Rails项目无法识别jQuery

Question

I have a project where I need to use jQuery for my javascript file. I get an error telling me 'Reference error: $ is not defined.' when I load my page from a line of code

$(window).load(function()

The full function is in the play.html.erb snippet below. I believe this is a jQuery error.

I am using Ruby 2.1.2p95 and Rails 4.1.6.

I have done some research on this as to how to get jQuery to work but nothing has helped. I looked at Installing jQuery in Rails 3.2.13

I have tried putting <%= javascript_include_tag "//ajax.googleapis.com/ajax/libs/jquery/1.10.1/jquery.min.js" %> in my html.erb file that includes the javascript file I am trying to use the jquery in

I have tried putting <%= javascript_include_tag :application %> in there as well.

There were suggestions to putting the entire file in my app/assets/javascript so I downloaded jquery-2.1.1.min,js and put that in there, and put the <%= javascript_include_tag "jquery-2.1.1.min" %> in the html.erb file and put Rails.application.config.assets.precompile += %w( jquery-2.1.1.min.js ) in my assets.rb and precompiled my assets through the terminal.

I have put the gem 'jquery-rails' in my gemfile.

I have also tried the 2 directions on https://rubygems.org/gems/jquery-rails

I have the normally specified requires in my application.js

I run bundle install after everything I tried just in case.

play.js

$(window).load(function()
{
    var c = document.getElementById("charhealthbar");
    var ctx = c.getContext("2d");
    var health = 5;
    ctx.fillStyle = "#FF0000";
    ctx.fillRect(0, 0, (health / 100) * 140, 25);
});

assets.rb

 Rails.application.config.assets.version = '1.0'   
 Rails.application.config.assets.precompile += %w( creation.css )
 Rails.application.config.assets.precompile += %w( Main.css )
 Rails.application.config.assets.precompile += %w( creation.js )
 Rails.application.config.assets.precompile += %w( play.css)
 Rails.application.config.assets.precompile += %w( play.js )
 Rails.application.config.assets.precompile += %w( jquery-2.1.1.min.js )

play.html.erb

  <%= stylesheet_link_tag "Main.css" %>
  <%= stylesheet_link_tag "play.css" %>
  <%= javascript_include_tag "play" %>
  <%= javascript_include_tag :application %>
  <%= javascript_include_tag "jquery-2.1.1.min" %>

application.js

//= require jquery
//= require jquery_ujs
//= require creation
//= require_tree .

Gemfile

source 'https://rubygems.org'
gem 'rails', '4.1.6'
gem 'pg'
gem 'sass-rails', '~> 4.0.3'
gem 'uglifier', '>= 1.3.0'
gem 'coffee-rails', '~> 4.0.0'
gem 'turbolinks'
gem 'jbuilder', '~> 2.0'
gem 'sdoc', '~> 0.4.0',          group: :doc
gem 'spring',        group: :development
gem 'jquery-rails'

I also currently still have the jquery-2.1.1.min.js in my app/assets/javascripts folder. Any help on fixing this error would be greatly appreciated.

Answer 1

You should put the include tag for "play" after the include tag for jquery :

  <%= stylesheet_link_tag "Main.css" %>
  <%= stylesheet_link_tag "play.css" %>
  <%= javascript_include_tag "jquery-2.1.1.min" %>
  <%= javascript_include_tag :application %>
  <%= javascript_include_tag "play" %>