function submenu(sm, sarr){
var submenu=document.getElementById(sm)
var subarrow=document.getElementById(sarr)
if (submenu.getAttribute("rel")=="closed"){
submenu.style.display="block"
submenu.setAttribute("rel", "open")
subarrow.src='_images/sub_arrowu.gif'
}
else if (submenu.getAttribute("rel")=="open"){
submenu.style.display="none"
submenu.setAttribute("rel", "closed")
subarrow.src='_images/sub_arrowd.gif'
}
}