function choose_header()
{
    var theTable = [ "Ballot", "Bois", "Chartreuse", "Fleur", "Glicine", "LAupDeVeran", "Mirroir", "Nuages", "Paille", "Sk8", "SudVercorsSilouhette", "Vercors", "VercorsBWNeige", "VercorsColorNeige", "VercorsColorNeige2" ];
  d = new Date();
  document.getElementById("header").style.backgroundImage = 'url("css/images/' + theTable[(d.getDate() % (theTable.length + 1))] + '.jpg")';
}


window['onload'] = function(){choose_header();};