In Joomla!, submenus can be shown either as one menu with two or more levels or as completely separate menu modules. To show how to do this, we will step through creating a two-level menu and then see how to show it either as one large menu or as separate parent and child menus.
In our example, we will create a menu called "Pets". It will have two top-level menu items called "Dogs" and "Cats". Under Dogs, we will have "Collies" and "Greyhounds". Under Cats we will have "Tabbies" and "Siamese". So the structure of the Pets menu will be as follows:
To create this structure, we create one menu with two levels of Menu Items. Note that we do this whether we want to have everything shown as one large menu or whether we want to create separate menu modules (one parent menu and two child menus). We'll see how to do this later on, when we create the modules.
Here are the steps to create the Menu and Menu Items.
When you get done, the Menu Item Manager should look like the following:
At this point, we've got the Menu and Menu Items done. Now we need to create the Menu Modules. In Joomla!, the Menu Module determines three main things: (1) what the menu looks like; (2) where on the page it will show; and (3) on which pages it will show. We will do two examples. In the first example, we will create one. Menu Module that shows all of the items in one menu. In the second, we will create three separate menu modules to show the Pets, Dogs, and Cats menus as separate modules.
To show this as one module, follow these steps:
Now, navigate to the front-end home page. You should see the Pets Menu as shown below:
Click on the Dogs Menu Item. The selected article displays and the Dogs menu expands to show the two submenu items, Collies and Greyhounds. Note that we can set a parameter in the Module Manager to always show submenu items. Here we have taken the default value of "No". Click on "Collies" and again the article changes. (Or it would if we had different articles for each Menu Item!) The screen should look like the one below:
Notice that the Breadcrumbs now shows three levels: Home, Dogs, Collies. Because we used submenus, Joomla! "knows" that Collies is under Dogs.
Now we will change our example to create three separate menus -- one for the top level (Dogs and Cats), one for the Dogs (Collies and Greyhounds), and one for the Cats (Tabbies and Siamese). To do this:
At this point, we have three menu modules all pointing to the Pets Menu. The only differences between them are (1) the Start and End Levels and (2) the Menu Item Assignment.
Now, in the front end, navigate to the Home page. The "Pets Menu Top Level Only" menu should show. Select the "Dogs" Menu Item. Now, the "Dogs Submenu" should show as a separate menu, as shown below:
Click on the Collies Menu Item and notice that again the Breadcrumbs shows the hierarchy of "Home", "Dogs", and "Collies".
Using this same technique, it is easy to create third-level submenus. You just make the Parent Menu Item a second-level submenu. Then you could use the same technique to create a separate Menu Module with Start Level of 2 and End Level of 3. This would show only the third-level Menu Items.