# jquery-rails-cdn Add CDN support to [jquery-rails](https://github.com/rails/jquery-rails). Serving jQuery from a publicly available [CDN](http://en.wikipedia.org/wiki/Content_Delivery_Network) has clear benefits: * **Speed**: Users will be able to download jQuery from the closest physical location. * **Caching**: CDN is used so widely that potentially your users may not need to download jQuery at all. * **Parallelism**: Browsers have a limitation on how many connections can be made to a single host. Using CDN for jQuery offloads a big one. ## Features This gem offers the following features: * Supports multiple CDN. (Google, Microsoft, jquery.com, etc.) * jQuery version is automatically detected via `jquery-rails`. * Automatically fallback to jquery-rails' bundled jQuery when: * You're on a development environment, so that you can work offline. * The CDN is down or unreachable. On top of that, if you're using asset pipeline, you may have noticed that the major chunks of the code in combined `application.js` is jQuery. Implications of externalizing jQuery from `application.js` are: * Updating your JS code won't evict the entire cache in browsers. * Cached jQuery in the client browsers will survive deployments. * Your code changes more often than jQuery upgrades, right? * `rake assets:precompile` will run faster and use less memory. Changelog: * v1.2.0: Support jQuery3. (Thanks to @CUnknown) * v1.1.0: Support jQuery2. (Thanks to @timurkhafizov) * v1.0.0: Options like `defer: true` or `data-turbolinks-eval: false` are allowed to be passed. (Thanks to @mkitt) * v0.4.0: Added Cloudflare. (Thanks to @damonmorgan) * v0.3.0: Microsoft and Yandex are now always scheme-less. (Thanks to @atipugin) * v0.2.1: Use minified version for Yandex. (Thanks to @atipugin) * v0.2.0: (Incompatible Change) Google CDN is now always scheme-less. Add Yandex CDN for Russian users. (Thanks to @ai) * v0.1.0: Added `:google_schemeless` for sites that support both SSL and non-SSL. * v0.0.1: Initial release ## Installation Add this line to your application's Gemfile: ```ruby gem 'jquery-rails-cdn' ``` ## Usage This gem adds two methods `jquery_include_tag` and `jquery_url`. If you're using asset pipeline with Rails 3.1+, - Remove `//= require jquery` from `application.js`. - Put the following line in `config/application.rb`, so that jquery.js will be served from your server when CDN is not available. ```ruby config.assets.precompile += ['jquery.js'] ``` Then in layout: ```ruby = jquery_include_tag :google = javascript_include_tag 'application' ``` Note that valid CDN symbols are `:google`, `:microsoft`, `:jquery`, `:cloudflare` and `:yandex`. Now, it will generate the following on production: ```html ``` on development: ```html ``` If you want to check the production URL, you can pass `force: true` as an option. ```ruby jquery_include_tag :google, force: true ``` ## jQuery 2 / jQuery 3 If you want to use jQuery 2, drop the following line in `config/initializers/jquery_cdn.rb`: ```ruby Jquery::Rails::Cdn.major_version = 2 ``` or for jQuery 3: ```ruby Jquery::Rails::Cdn.major_version = 3 ``` and then in `config/application.rb`: ```ruby config.assets.precompile += ['jquery2.js'] ``` or for jQuery 3: ```ruby config.assets.precompile += ['jquery3.js'] ``` ## jQuery UI To get the same CDN benefits with jQuery UI, we recommend [jquery-ui-rails-cdn](https://github.com/styx/jquery-ui-rails-cdn).