if(document.images){
var offs = new Array();
var ons = new Array();
for(i=1;i<14;i++)
	{
	offs[i] = new Image();
	ons[i] = new Image();
	offs[i].src = './pics/btn_'+i+'_off.gif';
	ons[i].src = './pics/btn_'+i+'_x.gif';
	}
}
function show(ImgNum)
{
if(document.images)
{document.images[ImgNum].src = ons[ImgNum].src;}
}
function hide(ImgNum)
{
if(document.images)
{document.images[ImgNum].src = offs[ImgNum].src;}
}