function insertStyle()
{
  if (window.innerWidth >= 1280 )
  {
    window.document.write('<link rel="stylesheet" type="text/css" href="/transvaal-gres/css/style1280.css" />');
  }
  if (window.innerWidth <= 1024)
  {
    window.document.write('<link rel="stylesheet" type="text/css" href="/transvaal-gres/css/style1024.css" />');
  }

}
function getWidth(innerWidth)
{
  var width = innerWidth * 240 / 1024;
  if ( innerWidth > 1280 ) width= 305; 
  if (innerWidth < 1024 ) width= 240;

  return width;
}
function changeImage(tab, category, div)
{
  // ON RECUPERE UNE IMAGE ALEATOIRE
  var image = tab[Math.round(Math.random()*(tab.length-1))];

    // ON MODIFIE L'IMAGE DE l'ARRIERE PLAN
    div.style.backgroundImage = 'url(/images/' + category + '/' + image+')';

  
  // ON APPELLE LA FONCTION TOUS LES 3 SECONDES
  setTimeout(function() {changeImage(tab, category, div) }, 3000);
}