window.onload = function() {
	//現在の月を取得
	var nowDate  = new Date();
	var nowMonth = nowDate.getMonth() + 1;
	
	//季節ごとに読み込む画像ファイルを変える
	var headImg; //headerの画像
	var bodyImg; //bodyの画像1
	var sideImg; //横の影
	if (nowMonth == 12 || (nowMonth >= 1 && nowMonth <= 2) ) {
		//12～2月は冬
		headImg = "../img/wphoto1.jpg";
		bodyImg = "../img/wBG.jpg";
		sideImg = "../img/wBG2.jpg";
	} else if (nowMonth >= 3 && nowMonth <= 8) {
		//3～8月は春、夏
		headImg = "../img/ssphoto2.jpg";
		bodyImg = "../img/ssBG.jpg";
		sideImg = "../img/ssBG2.jpg";
	/*} else if (nowMonth >= 6 && nowMonth <= 8) {
		//6～8月は夏
		headImg = "../img/ssphoto1.jpg";
		bodyImg = "../img/ssBG.jpg";
		sideImg = "../img/ssBG2.jpg";*/
	} else if (nowMonth >= 9 && nowMonth <= 11) {
		//9～11月は秋
		headImg = "../img/aphoto1.jpg";
		bodyImg = "../img/aBG.jpg";
		sideImg = "../img/aBG2.jpg";
	} else {
		//一応、例外処理
		alert("エラ～～！！");
	}
	
	//スタイルシートを変更
	document.getElementById('header').style.backgroundImage = "url(" + headImg + ")";
	document.getElementById('body').style.backgroundImage = "url(" + bodyImg + ")";
	if(document.all){
		if ( browser.match(/MSIE (\d+\.[0-9])/) ) {
			if (RegExp.$1 <= "6.0") {
				document.getElementById('wrapper').style.backgroundImage = "url(" + sideImg + ")";
			}
		}
	}
}