function showAtCenter(e,strLayer) {
      if (window.event) e = window.event;
      var oLayer = top.document.getElementById(strLayer);

      if (window.event) {
        var intClientWidth = top.document.body.clientWidth;
        var intClientHeight = top.document.body.clientHeight;
      } else {
        var intClientWidth = top.innerWidth;
        var intClientHeight = top.innerHeight;
      }

      var intWidth = top.document.body.scrollLeft + top.document.documentElement.scrollLeft + (intClientWidth / 2);
      var intHeight = top.document.body.scrollTop + top.document.documentElement.scrollTop + (intClientHeight / 2);

      var intLayerWidth = oLayer.style.width.substr(0,oLayer.style.width.length - 2);
      var intLayerHeight = oLayer.style.height.substr(0,oLayer.style.width.length - 2);

      var intNewLeft = (intWidth) - (intLayerWidth / 2);
      var intNewTop = (intHeight) - (intLayerHeight / 2);

      oLayer.style.left = intNewLeft + "px";
      oLayer.style.top = intNewTop + "px";
    }

    function mostrarCapa(str_name,e) {
      var mi_capa = document.getElementById(str_name);
      mi_capa.style.visibility = 'visible';
      mi_capa.style.display = "block";
      showAtCenter(e,str_name);
      return false;
    }

  function cerrarCapa(str_name) {
    var mi_capa = document.getElementById(str_name);
    mi_capa.style.visibility = 'hidden';
    mi_capa.style.display = "none";
    return false;
  }
  
  function setIframeSource(str_name,str_url) {
    top.frames[str_name].location.replace(str_url);
  }