janela = function(url,titulo,w,h,scrol){
	lado=(screen.width)?(screen.width-w)/2:100;
	cima=(screen.height)?(screen.height-h)/2-28:20;
	conf='resizable=yes,width='+w+',height='+h+',top='+cima+',left='+lado+',scrollbars='+scrol+',status=1';
	window.open(url,titulo,conf);
}