Ruby on Rails : Could not find a JavaScript runtime

[root@slave2 first]# rails s

/usr/local/rvm/gems/ruby-2.0.0-p481/gems/execjs-2.2.1/lib/execjs/runtimes.rb:51:in `autodetect': Could not find a JavaScript runtime. See https://github.com/sstephenson/execjs for a list of available runtimes. (ExecJS::RuntimeUnavailable) from/usr/local/rvm/gems/ruby-2.0.0-p481/gems/execjs-2.2.1/lib/execjs.rb:5:in `' from/usr/local/rvm/gems/ruby-2.0.0-p481/gems/execjs-2.2.1/lib/execjs.rb:4:in `' from/usr/local/rvm/gems/ruby-2.0.0-p481/gems/uglifier-1.3.0/lib/uglifier.rb:3:in `require' from/usr/local/rvm/gems/ruby-2.0.0-p481/gems/uglifier-1.3.0/lib/uglifier.rb:3:in `' from/usr/local/rvm/gems/ruby-2.0.0-p481@global/gems/bundler-1.6.2/lib/bundler/runtime.rb:76:in `require' from/usr/local/rvm/gems/ruby-2.0.0-p481@global/gems/bundler-1.6.2/lib/bundler/runtime.rb:76:in `block (2 levels) in require' from/usr/local/rvm/gems/ruby-2.0.0-p481@global/gems/bundler-1.6.2/lib/bundler/runtime.rb:72:in `each' from/usr/local/rvm/gems/ruby-2.0.0-p481@global/gems/bundler-1.6.2/lib/bundler/runtime.rb:72:in `block in require' from/usr/local/rvm/gems/ruby-2.0.0-p481@global/gems/bundler-1.6.2/lib/bundler/runtime.rb:61:in `each' from/usr/local/rvm/gems/ruby-2.0.0-p481@global/gems/bundler-1.6.2/lib/bundler/runtime.rb:61:in `require' from/usr/local/rvm/gems/ruby-2.0.0-p481@global/gems/bundler-1.6.2/lib/bundler.rb:132:in `require' from/root/rails/first/config/application.rb:7:in `' from/usr/local/rvm/gems/ruby-2.0.0-p481/gems/railties-4.0.2/lib/rails/commands.rb:74:in `require' from/usr/local/rvm/gems/ruby-2.0.0-p481/gems/railties-4.0.2/lib/rails/commands.rb:74:in `block in ' from/usr/local/rvm/gems/ruby-2.0.0-p481/gems/railties-4.0.2/lib/rails/commands.rb:71:in `tap' from/usr/local/rvm/gems/ruby-2.0.0-p481/gems/railties-4.0.2/lib/rails/commands.rb:71:in `' from bin/rails:4:in `require' from bin/rails:4:in `

[root@slave2 first]# yum install nodejs

Loaded plugins: fastestmirror, prestoLoading mirror speeds from cached hostfile * base: mirror.bit.edu.cn * epel: mirrors.yun-idc.com * extras: mirrors.yun-idc.com * updates: mirrors.yun-idc.comSetting up Install ProcessResolving Dependencies--> Running transaction check---> Package nodejs.x86_64 0:0.10.29-1.el6 will be installed--> Finished Dependency ResolutionDependencies Resolved======================================================================================================================================= Package Arch Version Repository Size=======================================================================================================================================Installing: nodejs x86_64 0.10.29-1.el6 epel 498 kTransaction Summary=======================================================================================================================================Install 1 Package(s)Total download size: 498 kInstalled size: 1.5 MIs this ok [y/N]: yDownloading Packages:Setting up and reading Presto delta metadataProcessing delta metadataPackage(s) data still to download: 498 knodejs-0.10.29-1.el6.x86_64.rpm | 498 kB 00:00 Running rpm_check_debugRunning Transaction TestTransaction Test SucceededRunning Transaction Installing : nodejs-0.10.29-1.el6.x86_64 1/1 Verifying : nodejs-0.10.29-1.el6.x86_64 1/1 Installed: nodejs.x86_64 0:0.10.29-1.el6 Complete!