$(document).ready(function(){
	
	var subNavigationDiv = $( '#sub_navigation' );
	var wrapperContent = $( '#wrapper_content' );
	var subNavigation = $( '#sub_navigation ul.sub_navigation' );
	var view = $( window );
	
	view.bind(
		'scroll resize',
		function(){
			var subNavigationDivTop = subNavigationDiv.offset().top-40;
			var viewTop = view.scrollTop();
			
			if(
				( viewTop > subNavigationDivTop )
				&& !subNavigation.hasClass( 'fixed' )
			)
			{				
				subNavigationDiv.addClass( 'sub_navigation_fixed' );
				wrapperContent.addClass( 'sub_navigation_fixed' );
				subNavigation.addClass( 'fixed' );
			}
			else if(
				( viewTop <= subNavigationDivTop )
				&& subNavigation.hasClass( 'fixed' )
			)
			{
				subNavigationDiv.removeClass( 'sub_navigation_fixed' );
				wrapperContent.removeClass( 'sub_navigation_fixed' );
				subNavigation.removeClass( 'fixed' );
			}
		}
	);
	
})(jQuery);