In this case, the default configuration is not fit my need. So, I change the configuration. Based on experience configuring Ubuntu 12.04, I try to apply this on Ubuntu 14.04 (local machine). This configuration is slightly different. Here is how to configure it;
1. Open /etc/apache2/apache2.conf and change the line "/var/www" into something like below;
<Directory /home/your_name/sites/> Options Indexes FollowSymLinks AllowOverride None Require all granted </Directory>
2. Open /etc/apache2/sites-available/000-default.conf and change the line "DocumentRoot /var/www/html" into something like below;
3. Create an index.html file in /home/your_name/sites/default folder.
4. Restart apache
$ sudo service apache2 restart
That's it! :)