// JavaScript Document
function abrirVentana (pagina, ancho, alto) {
    var iz = (screen.width - ancho)/2;
    var de = (screen.height - alto)/2;
 
    var opciones= "toolbar=no, location=no, directories=no, status=no, menubar=no, scrollbars=yes, resizable=no, width="+ancho+", height="+alto+", top="+de+", left="+iz+"";
    window.open(pagina,"",opciones);
}