function abre_janela(url, nome, width, height, scrollbar) 
{

	// --------------------------------------------------------------------
	// cria o código das janelas na página principal
	// --------------------------------------------------------------------

	var top; var left;
	top = ( (screen.height/2) - (height/2) )
	left = ( (screen.width/2) - (width/2) )
	window.open(url,nome,'width='+width+',height='+height+',scrollbars='+scrollbar+',toolbar=no,location=no,status=no,menubar=no,resizable=no,left='+left+',top='+top);

}