function ficha(pagina,ancho,alto,nomb,camb)
{
	x= (screen.height-alto)/2;
	y= (screen.width-ancho)/2;
	
	eval("window.open('"+pagina+"','"+nomb+"','toolbar=no,location=no,directories=no,status=no,scrollbars="+camb+",resizable=no,copyhistory=no,width="+ancho+",height="+alto+",top="+x+",left="+y+"')");
}