Begin by placing the markup for the two-column Grid on the page (this example uses the Grids Preset Template 1, 160px left). Add the markup for the MenuBar instance to the right column of the grid, appending the class of "yuimenubarnav" to the root element. The application of the "yuimenubarnav" class will render each item in the MenuBar instance with arrows to the right of each text label, providing a visual cue that the item contains a submenu.

Use the onContentReady method of the Event utility to instantiate the MenuBar as soon as its markup is available for scripting.

This MenuBar instance makes use of several configuration properties. Setting the "autosubmenudisplay" configuration property to "true" modifies its default behavior so that mousing over any item in the MenuBar automatically triggers the display of its submenu. The "hidedelay" configuration property is set to "750" so each submenu automatically hides 750ms after the user's mouse has left the menu. Lastly, the "lazyload" property is set to "true" to help speed up the initial load time of the MenuBar instance by deferring the initialization and rendering of each submenu until just before it is initially made visible.

Setup the animation for the submenus by subscribing to their "beforeShow" and "show" events. The "beforeShow" event handler will be used to collapse the height of the Menu instance before it is made visible. The "show" event handler will kick off an animation that increments the "marginTop" style property of each submenu's <ul> element from a negative value equal to its height to 0, causing the submenu to slowly expand to its original height as it is displayed.

Configuration for This Example

You can load the necessary JavaScript and CSS for this example from Yahoo's servers. Click here to load the YUI Dependency Configurator with all of this example's dependencies preconfigured.