function high(name,over)
{
if(top.document.images)
{
 if (over)
  top.document.images[name].src = "images/" + name + "_high.gif";
 else
  top.document.images[name].src = "images/" + name + ".gif";
}
}

function showLayer(layerid)
{
layer = document.getElementById(layerid);
layer.style.visibility = "visible";
}
function hideLayer(layerid)
{
layer = document.getElementById(layerid);
layer.style.visibility = "hidden";
}