function roll(img_name1, img_src1, img_name2, img_src2)
   {
   document[img_name1].src = img_src1;
   document[img_name2].src = img_src2;
   }
   
   if (document.images)
{
jpg01on=new Image (115,20);
jpg01on.src="nav_01b.jpg";
jpg01off=new Image (115,20);
jpg01off.src="nav_01a.jpg";

jpg02on=new Image (117,20);
jpg02on.src="nav_02b.jpg";
jpg02off=new Image (117,20);
jpg02off.src="nav_02a.jpg";

jpg03on=new Image (116,20);
jpg03on.src="nav_03b.jpg";
jpg03off=new Image (116,20);
jpg03off.src="nav_03a.jpg";

jpg04on=new Image (117,20);
jpg04on.src="nav_04b.jpg";
jpg04off=new Image (117,20);
jpg04off.src="nav_04a.jpg";

jpg05on=new Image (111,20);
jpg05on.src="nav_05b.jpg";
jpg05off=new Image (111,20);
jpg05off.src="nav_05a.jpg";

}
function over (imgName)
{
if (document.images)
{
imgOn=eval (imgName + "on.src");
document[imgName].src=imgOn;
}
}
function off (imgName)
{
if (document.images)
{
imgOff=eval (imgName + "off.src");
document[imgName].src=imgOff;
}
}