if (document.images) 
{
	var guides_off=new Image();
	guides_off.src="images/guides_off.jpg";
	var guides_on=new Image();
	guides_on.src="images/guides_on.jpg";
	var quiz_off=new Image();
	quiz_off.src="images/quiz_off.jpg";
	var quiz_on=new Image();
	quiz_on.src="images/quiz_on.jpg";
	var game_off=new Image();
	game_off.src="images/game_off.jpg";
	var game_on=new Image();
	game_on.src="images/game_on.jpg";
	var forum_off=new Image();
	forum_off.src="images/forum_off.jpg";       
	var forum_on=new Image();
	forum_on.src="images/forum_on.jpg";     
	var search_off=new Image();
	search_off.src="images/search_off.jpg";       
 	var search_on=new Image();
	search_on.src="images/search_on.jpg";
	var links_off=new Image();
	links_off.src="images/links_off.jpg";       
 	var links_on=new Image();
	links_on.src="images/links_on.jpg";
	var about_off=new Image();
	about_off.src="images/about_off.jpg";       
 	var about_on=new Image();
	about_on.src="images/about_on.jpg";
}

function over(imgName) 
{
	if(document.images) 
		document[imgName].src = eval(imgName + "_on.src");
}

function out(imgName) 
{
	if(document.images)
		document[imgName].src = eval(imgName + "_off.src");
}