Adjusting a core Joomla file (i.e., the files that you uploaded before installing Joomla!). Any changes you make to core files will be overwritten during the next update, thus core hack is not recommended. In most cases, there are alternative workaround to change Joomla without hacking the core.

A scripting language that runs inside the client browser, used in many web applications. In Joomla, JavaScript has become an important part to enhance the user interface and provide AJAX functionality.

A file that stores configuration setttings which you will find in the root folder of Joomla installation. All the parameters under the Site, System and Server tabs in the Global Configuration are stored as values in this file. This file is set up automatically by the software installation process and thus many of the parameters appearing in the Global Configuration screens are best left as their initial settings.