如何在apache2中允许跨域请求

这是我的配置文件.

<VirtualHost *:80>
    ServerAdmin webmaster@localhost
    ServerName localhost:80
    DocumentRoot /var/www/XXX
    <Directory />
        Options None
        AllowOverride None
        Order deny,allow
        Deny from all
    </Directory>
    <Directory /var/www/qvbn-app-web-ctrl>
        Options FollowSymLinks
        AllowOverride AuthConfig FileInfo
        Order allow,deny
        Allow from all
        Header set Access-Control-Allow-Origin "*"
    </Directory>
    ErrorLog ${APACHE_LOG_DIR}/error.log
    LogLevel warn
    CustomLog ${APACHE_LOG_DIR}/access.log combined
</VirtualHost>

当我尝试重新加载apache2时，iT发出错误消息:

When i am trying to reload apache2 iT is giving error as :

   Invalid command 'Header', perhaps misspelled or defined by a module not included in the server configuration
    Action 'configtest' failed.

我不知道如何启用CORS.我遵循了这一点: http://enable-cors.org/server_apache.html

I don't know how to enable CORS. I followed this: http://enable-cors.org/server_apache.html