function ChangeTableBack()
{
//------------------------------------------------------------
//javascript by ＠うさ http://www.usagi-js.com/
//------------------------------------------------------------
	//URLを指定していれておきます。
	var arrUrl = new Array("top_bg/top_bg.jpg",
			"top_bg/top_bg2.jpg",
			"top_bg/top_bg3.jpg",
			"top_bg/top_bg4.jpg",
			"top_bg/top_bg5.jpg",
			"top_bg/top_bg6.jpg",
			"top_bg/top_bg7.jpg",
			"top_bg/top_bg8.jpg",
			"top_bg/top_bg9.jpg",
			"top_bg/top_bg10.jpg",
			"top_bg/top_bg11.jpg",
			"top_bg/top_bg12.jpg",
			"top_bg/top_bg13.jpg",
			"top_bg/top_bg14.jpg",
			"top_bg/top_bg15.jpg",
			"top_bg/top_bg16.jpg",
			"top_bg/top_bg17.jpg")
	//処理スタート
	nTemp = Math.round(Math.random()*(arrUrl.length-1));
	strHtml = "url("+arrUrl[nTemp]+")";
	document.getElementById("tblSample").style.background = strHtml;
}