$(document).ready(function() {
  
  /*
    luzes verdes
    http://flickr.com/photos/franklinheijnen/3051965379/sizes/l/

    beer
    http://flickr.com/photos/freya_gefn/2778029784/sizes/l/

    globo
    http://flickr.com/photos/wollbinho/2770566567/sizes/o/
    
    tampa heineken
    http://flickr.com/photos/manel/283964150/sizes/o/
    
    logos cerveja
    http://flickr.com/photos/steve-n-leona/52572520/sizes/l/
    
    garrafa na praia
    http://flickr.com/photos/yaced/2790558707/sizes/l/
  */
  $('body').css('background-image', 'url("bg' + randRange(1,6) + '.jpg")')
});

// numero aleatorio num intervalo, inclusivo
function randRange(lowVal,highVal) {
     return Math.floor(Math.random()*(highVal-lowVal+1))+lowVal;
}