我的電腦系統及Rails版本：CentOS 7，Rails4.1.6，Ruby2.0.0
1啟動服務器後報錯
#rails server
剛建的新項目，啟動服務報錯：
/home/oss/.gem/ruby/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 /home/oss/.gem/ruby/gems/execjs-2.2.1/lib/execjs.rb:5:in `<module:ExecJS>'
from /home/oss/.gem/ruby/gems/execjs-2.2.1/lib/execjs.rb:4:in `<top (required)等等
解決方法：
方法一：
1實際報錯信息都已經給出來了解決鏈接https://github.com/sstephenson/execjs，在上邊的報錯信息中
看過後直接安裝這個就行了therubyracer
參考該插件的說明：https://github.com/sstephenson/execjs#readme
安裝命令
#gem install therubyracer
過程的成功的信息如下：
[oss@localhost t9]$ gem install therubyracer
Fetching: ref-1.0.5.gem (100%)
Successfully installed ref-1.0.5
Fetching: libv8-3.16.14.7-x86_64-linux.gem (100%)
Successfully installed libv8-3.16.14.7-x86_64-linux
Fetching: therubyracer-0.12.1.gem (100%)
Building native extensions. This could take a while...
Successfully installed therubyracer-0.12.1
Parsing documentation for ref-1.0.5
Installing ri documentation for ref-1.0.5
Parsing documentation for libv8-3.16.14.7-x86_64-linux
Installing ri documentation for libv8-3.16.14.7-x86_64-linux
Parsing documentation for therubyracer-0.12.1
Installing ri documentation for therubyracer-0.12.1
Done installing documentation for ref, libv8, therubyracer after 1 seconds
3 gems installed
說明沒有問題，安張了三個gem都成功了
方法二：
（1）修改你新建的項目的根目錄下的Gemfile
# vi Gemfile
找到下面這行，把注釋去掉，
# gem 'therubyracer', platforms: :ruby
修改為
gem 'therubyracer', platforms: :ruby
保存退出 #wq
（2）用bundle安裝即可
#bundle install
參考rails4 Guides：http://guides.ruby-china.org/getting_started.html
方法三：
(3)把execjs和therubyracer都不要了，卸載掉然後安裝nodejs即可
官網http://nodejs.org/
下載後安裝就行了
#tar -xzvf node-v0.10.31.tar.gz
#cd node-v0.10.31
# ./configure
#make
#make install
Rails 的詳細介紹：請點這裡
Rails 的下載地址：請點這裡
Ubuntu下Apache服務器安裝以及使用Passenger插件部署Rails應用 http://www.linuxidc.com/Linux/2012-12/75230.htm
Ubuntu下搭建Ruby On Rails http://www.linuxidc.com/Linux/2012-06/61981.htm
