var browser = {
  'agent' : navigator.userAgent.toLowerCase(),
  'major' : parseInt(navigator.appVersion),
  'minor' : parseFloat(navigator.appVersion),
  'name' : function() {
    return (navigator.appName.toLowerCase() == 'netscape' ? 'firefox' :
           ((navigator.appName.toLowerCase().indexOf('microsoft') == 0) ? 'internet explorer' : 'outro'))
  },
  'version' : function() {
    if (this.name() == 'firefox') {
      return (parseInt(this.agent.split(/firefox\/((.*))$/g)[1]) >= 3);
    }
    else if (this.name() == 'internet explorer') {
      return (this.agent.indexOf("msie 8.") != -1);
    }
  }
};

function fancy_shadow() {
  if (!browser.version()) {
    var fw = '487';
    var fh = '287';
    var sw = screen.width;
    var sh = screen.height;
    var pt = (sh-fh)/4;
    var pl = (sw-fw)/2;
    
    var bloco = document.getElementById('block_outer');
    bloco.style.left = pl + 'px';
    bloco.style.top = pt + 'px';
    
    var mensagem = 'Este site é melhor visualizado nos navegadores Internet Explorer 8 e Mozilla Firefox 3';
    document.getElementById('shadow_ads').style.display = 'block';
    document.getElementById('bloco_mensagem').innerHTML = mensagem;

    document.getElementById('close_message').onclick = function(){
      document.getElementById('shadow_ads').style.display = 'none';
    };
  }
}