function showElement(element_id)
{
   if (document.getElementById &&
         document.getElementById(element_id) &&
         document.getElementById(element_id).style)
   {
   document.getElementById(element_id).style.visibility="visible";
   };
}

function hideElement(element_id)
{
   if (document.getElementById &&
         document.getElementById(element_id) &&
         document.getElementById(element_id).style)
   {
   document.getElementById(element_id).style.visibility="hidden";
   };
}

function changeImage(layer,imgName,imgObj) {
	if (document.images) {
		if (document.layers && layer!=null) eval('document.'+layer+'.document.images["'+imgName+'"].src = '+imgObj+'.src')
		else document.images[imgName].src = eval(imgObj+".src")
	}
}