var flag; 
 
	nav_overview_on = new Image(); 
	nav_overview_on.src = "../../jpgs/navigation/main_nav_overview_on.jpg"; 
	nav_overview_off = new Image(); 
	nav_overview_off.src = "../../jpgs/navigation/main_nav_overview_off.jpg"; 
 
	nav_basics_on = new Image(); 
	nav_basics_on.src = "../../jpgs/navigation/main_nav_basics_on.jpg"; 
	nav_basics_off = new Image(); 
	nav_basics_off.src = "../../jpgs/navigation/main_nav_basics_off.jpg"; 
 
	nav_special_on = new Image(); 
	nav_special_on.src = "../../jpgs/navigation/main_nav_special_on.jpg"; 
	nav_special_off = new Image(); 
	nav_special_off.src = "../../jpgs/navigation/main_nav_special_off.jpg"; 
 
	nav_resources_on = new Image(); 
	nav_resources_on.src = "../../jpgs/navigation/main_nav_resources_on.jpg"; 
	nav_resources_off = new Image(); 
	nav_resources_off.src = "../../jpgs/navigation/main_nav_resources_off.jpg";
	
	nav_overview_whychoose_on = new Image(); 
	nav_overview_whychoose_on.src = "../../jpgs/overview/subnav/overview_whychoose_on.jpg"; 
	nav_overview_whychoose_off = new Image(); 
	nav_overview_whychoose_off.src = "../../jpgs/overview/subnav/overview_whychoose_off.jpg"; 
 
	nav_overview_choosing_on = new Image(); 
	nav_overview_choosing_on.src = "../../jpgs/overview/subnav/overview_choosing_on.jpg"; 
	nav_overview_choosing_off = new Image(); 
	nav_overview_choosing_off.src = "../../jpgs/overview/subnav/overview_choosing_off.jpg"; 
 
	nav_overview_profdev_on = new Image(); 
	nav_overview_profdev_on.src = "../../jpgs/overview/subnav/overview_profdev_on.jpg"; 
	nav_overview_profdev_off = new Image(); 
	nav_overview_profdev_off.src = "../../jpgs/overview/subnav/overview_profdev_off.jpg";
	
	nav_basics_ti10_on = new Image(); 
	nav_basics_ti10_on.src = "../../jpgs/basics/subnav/basics_ti10_on.jpg"; 
	nav_basics_ti10_off = new Image(); 
	nav_basics_ti10_off.src = "../../jpgs/basics/subnav/basics_ti10_off.jpg"; 
 
	nav_basics_ti15_on = new Image(); 
	nav_basics_ti15_on.src = "../../jpgs/basics/subnav/basics_ti15_on.jpg"; 
	nav_basics_ti15_off = new Image(); 
	nav_basics_ti15_off.src = "../../jpgs/basics/subnav/basics_ti15_off.jpg"; 
	
	nav_special_auto_on = new Image(); 
	nav_special_auto_on.src = "../../jpgs/special/subnav/special_auto_on.jpg"; 
	nav_special_auto_off = new Image(); 
	nav_special_auto_off.src = "../../jpgs/special/subnav/special_auto_off.jpg"; 
 
	nav_special_man_on = new Image(); 
	nav_special_man_on.src = "../../jpgs/special/subnav/special_man_on.jpg"; 
	nav_special_man_off = new Image(); 
	nav_special_man_off.src = "../../jpgs/special/subnav/special_man_off.jpg"; 
 
 	nav_special_placevalue_on = new Image(); 
	nav_special_placevalue_on.src = "../../jpgs/special/subnav/special_placevalue_on.jpg"; 
	nav_special_placevalue_off = new Image(); 
	nav_special_placevalue_off.src = "../../jpgs/special/subnav/special_placevalue_off.jpg"; 
 
 	nav_special_fractions_on = new Image(); 
	nav_special_fractions_on.src = "../../jpgs/special/subnav/special_fractions_on.jpg"; 
	nav_special_fractions_off = new Image(); 
	nav_special_fractions_off.src = "../../jpgs/special/subnav/special_fractions_off.jpg"; 
 
 	nav_special_division_on = new Image(); 
	nav_special_division_on.src = "../../jpgs/special/subnav/special_division_on.jpg"; 
	nav_special_division_off = new Image(); 
	nav_special_division_off.src = "../../jpgs/special/subnav/special_division_off.jpg"; 
 
 	nav_special_constant_on = new Image(); 
	nav_special_constant_on.src = "../../jpgs/special/subnav/special_constant_on.jpg"; 
	nav_special_constant_off = new Image(); 
	nav_special_constant_off.src = "../../jpgs/special/subnav/special_constant_off.jpg"; 
 
	// FUNCTIONS 
	function 
	img_act_panel(imgName,flg) { 
	if(flg==flag){return;} 
	imgon = eval(imgName + "_on.src"); 
	document [imgName].src = imgon; 
	} 
 
	function 
	img_inact_panel(imgName,flg) { 
	if(flg==flag){return;} 
	imgoff = eval(imgName + "_off.src"); 
	document [imgName].src = imgoff; 
	}