function ApriCentrato(pagina,nome,width,height)
{
	 if(document.all)
	 {
	  var x = window.screenLeft;
	  var y = window.screenTop;
	  var w = window.document.body.offsetWidth;
	  var h = window.document.body.offsetHeight;
	 }
	 else
	 {
	  var x = window.screenX;
	  var y = window.screenY;
	  var w = window.outerWidth;
	  var h = window.outerHeight;
	 }
	 var left = x + Math.round((w - width) / 2);
	 var top = y + Math.round((h - height - 20) / 2)-300;
	 window.open(pagina,nome,'toolbar=no,status=no,scrollbars=yes,left='+left+',top='+ top+',width='+width+',height='+ height);
}