var SetBackgroudPicture = function() {
    var season = new Array();
    season[0] = "winter";
    season[1] = "winter";
    season[2] = "spring";
    season[3] = "spring";
    season[4] = "spring";
    season[5] = "summer";
    season[6] = "summer";
    season[7] = "summer";
    season[8] = "fall";
    season[9] = "fall";
    season[10] = "fall";
    season[11] = "winter";
    var currentDate = new Date();
    var currentMonth = parseInt(currentDate.getMonth());

    document.body.className = season[currentMonth] + "_style";
}