function OpenLayer(layer,top){
	layerWidth = document.getElementById(layer).style.width;
	layerWidth = layerWidth.replace("px","")
	screenwidth = screen.width;
	document.getElementById(layer).style.left = (screenwidth-layerWidth)/2+'px';
	if(top != ''){
		document.getElementById(layer).style.top = top+'px';
	}
	document.getElementById(layer).style.visibility='visible';
}
function CloseLayer(layer){
	document.getElementById(layer).style.visibility='hidden';
}