//ローテーション基本設定
var headerImgBoxName = "headerfotoBox";
var headerImgName = "headerfoto"; 
var browsSeconds = 8;
var opacityGrade = 5;
var imgOpacity = 100;
var randomImg = 0;

//最初の写真を決定
function headerRotate() {
	randomImg = Math.floor(Math.random() * photos.length);
	document.write('<img id="headerfoto" width="500" height="256" src="' +photos[randomImg] + '" />');
}


//フェード
function imgFade() {
	var imgObj = document.getElementById(headerImgName);
	if (imgOpacity <= opacityGrade) {//フェード外
		imgOpacity = 100;
		imgSelect();
		setTimeout("imgFade()",browsSeconds*1000);
	}else{//フェード中
		imgOpacity -= opacityGrade;
		setOpacity(imgObj,imgOpacity);
		setTimeout("imgFade()",50);
	}
}

//次の写真を選択
function imgSelect() {
	var divObj = document.getElementById(headerImgBoxName);
	var imgObj = document.getElementById(headerImgName);
	imgObj.src = photos[randomImg];
	setOpacity(imgObj,100);
	randomImg = Math.floor(Math.random() * photos.length);
	divObj.style.backgroundImage = 'url(' + photos[randomImg] + ')';
}

//不透明度設定
function setOpacity(obj, opacity)
{
	opacity = (opacity == 100)?100:opacity;
	obj.style.filter = "alpha(opacity:"+opacity+")";	
	obj.style.KHTMLOpacity = opacity/100;
	obj.style.MozOpacity = opacity/100;
	obj.style.opacity = opacity/100;
}





<!--HPB_SCRIPT_ROV_50
//
//  Licensed Materials - Property of IBM
//  5724G06
//  (C) Copyright IBM Corp. 1995, 2003 All Rights Reserved.
//

// HpbImgPreload:
//
function HpbImgPreload()
{
  var appVer=parseInt(navigator.appVersion);
  var isNC=false,isN6=false,isIE=false;
  if (document.all && appVer >= 4) isIE=true; else
    if (document.getElementById && appVer > 4) isN6=true; else
      if (document.layers && appVer >= 4) isNC=true;
  if (isNC||isN6||isIE)
  {
    if (document.images)
    {
      var imgName = HpbImgPreload.arguments[0];
      var cnt;
      swImg[imgName] = new Array;
      for (cnt = 1; cnt < HpbImgPreload.arguments.length; cnt++)
      {
        swImg[imgName][HpbImgPreload.arguments[cnt]] = new Image();
        swImg[imgName][HpbImgPreload.arguments[cnt]].src = HpbImgPreload.arguments[cnt];
      }
    }
  }
}
// HpbImgFind:
//
function HpbImgFind(doc, imgName)
{
  for (var i=0; i < doc.layers.length; i++)
  {
    var img = doc.layers[i].document.images[imgName];
    if (!img) img = HpbImgFind(doc.layers[i], imgName);
    if (img) return img;
  }
  return null;
}
// HpbImgSwap:
//
function HpbImgSwap(imgName, imgSrc)
{
  var appVer=parseInt(navigator.appVersion);
  var isNC=false,isN6=false,isIE=false;
  if (document.all && appVer >= 4) isIE=true; else
    if (document.getElementById && appVer > 4) isN6=true; else
      if (document.layers && appVer >= 4) isNC=true;
  if (isNC||isN6||isIE)
  {
    if (document.images)
    {
      var img = document.images[imgName];
      if (!img) img = HpbImgFind(document, imgName);
      if (img) img.src = imgSrc;
    }
  }
}
var swImg; swImg=new Array;
//-->



<!--HPB_SCRIPT_PLD_50
HpbImgPreload('_HPB_ROLLOVER1', 'image/bar-7.jpg', 'image/bar-7b.jpg');
HpbImgPreload('_HPB_ROLLOVER8', 'image/bar-1.jpg', 'image/bar-1b.jpg');
HpbImgPreload('_HPB_ROLLOVER9', 'image/bar-2.jpg', 'image/bar-2b.jpg');
HpbImgPreload('_HPB_ROLLOVER10', 'image/bar-3.jpg', 'image/bar-3b.jpg');
HpbImgPreload('_HPB_ROLLOVER13', 'image/bar-6.jpg', 'image/bar-6b.jpg');
HpbImgPreload('_HPB_ROLLOVER12', 'image/bar-5.jpg', 'image/bar-5b.jpg');
//-->