var dd = {
	
	menuID:'topNav',
	subMenuClass:'subMenu',
	numberOfMenus:6,
	
	menus:Array(),
	
	init:function() {
		
		if(!document.getElementById( dd.menuID )) return;
		
		dd.setMenus();
		
	},
	
	setMenus:function() {
		
		var mainNav = document.getElementById( dd.menuID );
		var allListItems = mainNav.getElementsByTagName( 'li' );
				
		for( var i=0; i < allListItems.length; i++ ) {
			
			if( allListItems[i].getElementsByTagName( 'ul' ).length > 0 ) {
				
				dd.menus[ dd.menus.length ] = allListItems[i];
				
			}
			
		}
		
		dd.addBehavior();
		
	},
	
	addBehavior:function() {
		
		for( var i=0; i< dd.menus.length; i++ ) {
			
			dd.menus[i].onmouseover = function() {
				
				
				dd.showSubMenu( this );
				return false;
				
			}
			
			dd.menus[i].onmouseout = function() {
				
				dd.hideSubMenu( this );
				return false;
				
			}
			
		}
		
	},
	
	showSubMenu:function( elem ) {
		
		var subMenu = elem.getElementsByTagName( 'ul' )[0];
		subMenu.style.display = 'block';
		
	},

	hideSubMenu:function( elem ) {
		
		var subMenu = elem.getElementsByTagName( 'ul' )[0];
		subMenu.style.display = 'none';
		
	},
	
	addLoadEvent:function( func ) {
		
		var oldonload = window.onload;
		
		if(typeof window.onload != 'function' ) {
			
			window.onload = func;
			
		} else {
			
			window.onload = function() {
				
				oldonload();
				func();
				
			}
			
		}
		
	}
	
}

dd.addLoadEvent( dd.init );