/*--------------------------------
  月毎の画像をセットする関数
--------------------------------*/
function set_month_image(){
  if(document.getElementById){
    var nowM=new Date().getMonth();
    nowM=nowM+1;
    if(nowM < 10){
      nowM = "0" + nowM; 
    }
    var header=document.getElementById("header-inner");
    header.style.backgroundImage="url(/general_image/month/" + nowM + ".jpg)";
  }
}