function exemplo(pagina,w,h) {
	//alert(pagina);
	var wint = (screen.width - w) / 2;
	var winl = (screen.height - h) / 2;
	novajanela = window.open('./exemplos/'+pagina,'janela','toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=no,resizable=no,menubar=no,top='+wint+',left='+winl+',width='+w+',height='+h);	
	novajanela.focus();
}