var nav_img = nav_img;
var nav_img_x = nav_img_x;

if (document.images)
	{
	nav_img = new Image(20,20); nav_img.src = "images/off.gif";
	nav_img_x = new Image(20,20); nav_img_x.src = "images/on.gif";
	}

function roll_over(X)
	{ if (document.images) { document[X].src = nav_img_x.src; } }

function roll_out(X)
	{ if (document.images) { document[X].src = nav_img.src; } }