var SLIDE_DOWN_SPEED = 300
var SLIDE_UP_SPEED = 300
var NAV_BUTTON_HEIGHT = 36



$(document).ready(
    function()
    {
        ConfigureNavButton('nav_item_02', '.nav_item_02_dropmenu-container', '.nav_item_02_dropmenu-list');
        ConfigureNavButton('nav_item_03', '.nav_item_03_dropmenu-container', '.nav_item_03_dropmenu-list');
        ConfigureNavButton('nav_item_04', '.nav_item_04_dropmenu-container', '.nav_item_04_dropmenu-list');
    }
);


function ConfigureNavButton(div, containerClass, listClass)
{
    var container = $(containerClass);
    var list = $(listClass);
    
    var initialHeight = list.height();
    list.css('opacity', '0.4');
     
    // Slide down functionality.
    container.mouseenter(
        function()
        {
            // JQuery alpha slide down effect.
            list.height(0);
            list.animate({ height: initialHeight, opacity: 1.0 }, { duration: SLIDE_DOWN_SPEED });
            
            // Change appropriate nav button to yellow.
            switch (div)
            {
                case "nav_item_02": document.getElementById(div).style.backgroundImage = 'url(http://www.understand.com/Assets/Images/Master_NavBtn_Physician-Products_On.png)'; break;
                case "nav_item_03": document.getElementById(div).style.backgroundImage = 'url(http://www.understand.com/Assets/Images/Master_NavBtn_Corporate-Solutions_On.png)'; break;
                case "nav_item_04": document.getElementById(div).style.backgroundImage = 'url(http://www.understand.com/Assets/Images/Master_NavBtn_Store_On.png)'; break;
            }
            
            // Extend main nav div downward so IE7 doesn't trigger the mouseleave event.
            document.getElementById(div).style.height = 200;
        }

    )
    
     // Slide up functionality.
    container.mouseleave(
        function()
        {
            // JQuery alpha slide up effect.
            list.stop(true, false).animate(
                { height: 0, opacity: 0.4 },
                { duration: SLIDE_UP_SPEED,
                  complete: function(){ list.hide(); list.height(initialHeight) }
                }
            );
            
            // Change appropriate nav button back to blue.
            switch (div)
            {
                case "nav_item_02": document.getElementById(div).style.backgroundImage = 'url(http://www.understand.com/Assets/Images/Master_NavBtn_Physician-Products.png)'; break;
                case "nav_item_03": document.getElementById(div).style.backgroundImage = 'url(http://www.understand.com/Assets/Images/Master_NavBtn_Corporate-Solutions.png)'; break;
                case "nav_item_04": document.getElementById(div).style.backgroundImage = 'url(http://www.understand.com/Assets/Images/Master_NavBtn_Store.png)'; break;
            }
            
            // Reset the main nav div height so that html text can still be highlighted.
            document.getElementById(div).style.height = 36;            
        }
    )
}