function roll_over(img_order) {    
    
    var img_name = [
      ['mision', ''],
      ['valores', ''],      
      ['servicios', ''],
      ['conferencias', ''],
      ['equipo', ''],
      ['clientes', '']      
  ];
  
    var img = document.getElementById('poster');
    img.src = '/images/rollover/' + img_name[img_order][0] + '.jpg';
    img.alt = img_name[img_order][1];

}

function preload() {
    var pre = new Image(0, 0);
    pre.src = "http://www.ajedrezyempresa.com/images/rollover/mision.jpg";
    var pre = new Image(0, 0);
    pre.src = "http://www.ajedrezyempresa.com/images/rollover/conferencias.jpg";
    var pre = new Image(0, 0);
    pre.src = "http://www.ajedrezyempresa.com/images/rollover/contacto.jpg";
    var pre = new Image(0, 0);
    pre.src = "http://www.ajedrezyempresa.com/images/rollover/equipo.jpg";
    var pre = new Image(0, 0);
    pre.src = "http://www.ajedrezyempresa.com/images/rollover/servicios.jpg";
    var pre = new Image(0, 0);
    pre.src = "http://www.ajedrezyempresa.com/images/rollover/clientes.jpg";
    var pre = new Image(0, 0);
    pre.src = "http://www.ajedrezyempresa.com/images/rollover/valores.jpg";    
}