function layer(id){
	var res
	if(document.getElementById) res=document.getElementById(id)
	if(document.all) res=document.all[id]
	if (res) return res.style
	return null
}

function show(id) {
	var hlp=layer(id)
	if (hlp) {
		hlp.visibility='visible'
	}	
}

function hide(id) {
	var hlp=layer(id)
	if(hlp) hlp.visibility='hidden'
}