extension-managerExtensions are software that works with the core Joomla installation, but extends it's functionality in some manner.  An Extension might allow you to have a slideshow for your graphics, enable you to create subscriptions and memberships, set up an event calendar, create an interface for e-commerce and a shopping cart, or multiple other things.

The core installation of Joomla has built in Extensions.  For other specific functionality you can visit  extensions.joomla.org and browse through hundreds of other extensions.  The Extensions listed there are by third party developers that have specifically written the software to work with the Joomla environment. Some Extensions are free, others require that you purchase them through the third party developers.  If the Extensions are listed on the Joomla site, they are generally considered safe.  You can find Extensions that are not on this list, but you could introduce your site to security risks and or cause you site to break or have conflict with other extensions.

There is a list of known Extensions that have had vulnerability problems.  You can find this list at  docs.joomla.org/Vulnerable_Extensions_List.  Some of these Extensions on this list have had bug fixes, so pay attention to what version had the vulnerability.

Another thing to watch out for is for what version of Joomla the Extension is written. Joomla has been around for quite some time and there are several versions.  The most common versions that you will see on the Extension list are 1.5, 2.5 and 3.0. You must match the version of Joomla in which your site is written before installing it.

Caution:  It is good practice to backup your site and your database before installing any Extension.  These software programs are written by separate companies and there can be conflicts that break your site.  If you have a backup, you can restore your site to the state it was in prior to installing the Extension relatively easily if you have a recent backup.

Learn by Example

We are going back to Thomas Greenthumb ans his site that he is developing for his garden center and landscaping and consulting services.  Thomas wants to add a free Extension named JCE Editor.  It is a very popular Extension that enhances the TinyMCE editor that comes with the Joomla core installation.

Thomas can either go to extensions.joomla.org and find the JCE Editor listing by searching for it, then clicking on the download link that takes him to the developer's site. Since he has installed it before, he knows that he can go straight to  www.joomlacontenteditor.net, because they are the developers that wrote the software and have the download available.  JCE Editor is a free download, but they also have many other Extensions that enhance Joomla's functionality that are available for purchase.

Note: Even if you have recently used a Extension download for a separate website, it is good practice to always go to the developer's site and download the most recent version.  The Extension my be written for Joomla 3.0, but developers are continuously updating their software with bug fixes, security fixes and added functionality.

Thomas is installing Joomla 3.03, so he finds the JCE Editor download that works with that version of Joomla.  He clicks on the download button and stores the .zip file temporarily on his own computer.  In this case he does NOT unzip it.  Some Extensions do have several .zip files within the download .zip file.  In this case the download file is usually named Unzip_First or something similar.  In that case you would unzip it on your own computer then upload the appropriate .zip file from there.

Next, Thomas logs into the Administrator Interface side of his site.  He goes to the menu item along the top that says Extensions and pulls it down to Extension Manager. He can also get to Extension Manager from the Quick Icons on the Dashboard. He makes sure that he is in the Install section by what is highlighted in the list of functions on the left hand side. There are three ways that you can upload an Extension in Joomla.  This is reviewed in the joom3 Administrative Interface section.

Thomas is going to the tab that is labels Upload Package File.  He gets to the com_jce_2324.zip file on his own computer by clicking on the button that reads Choose File.  He navigates to where the file is stored on his computer, highlights the zip file and selects Open in the lower right corner. Joomla takes him back to the Upload Package File tab and he clicks on Upload & Install.  Joomla does the work of unzipping the file and installing it in the proper location in the Joomla files on his hosting server.  This is one of the benefits of a CMS system.  Most Extensions will let you know right after installing in Extension Manager what all was installed, some instructions, and/or if a component or plugin requires enabling.

Thomas con then see JCE Editor on the drop down list under Components.  In some cases you need to enable the Component under the Manage function in Extension Manager.  In this case JCE Editor is already enabled.

Thomas now needs to set JCE Editor as the default text editor. He pulls down the System menu and goes to Global Conficuration. In the Site tab he selects Editor - JCE as the default editor.  There are other settings that he will need to make for JCE Editor, that is covered under the joomCommonly Used Extensions section.