<script type="text/javascript">
<!--
//共有幾張圖
var myImg = new Array("myImg/000.jpg","myImg/001.jpg","myImg/002.jpg","myImg/003.jpg","myImg/004.jpg","myImg/005.jpg","myImg/006.jpg","myImg/007.jpg","myImg/008.jpg","myImg/009.jpg","myImg/010.jpg","myImg/011.jpg","myImg/012.jpg","myImg/013.jpg","myImg/014.jpg","myImg/015.jpg","myImg/016.jpg","myImg/017.jpg","myImg/018.jpg","myImg/019.jpg","myImg/020.jpg","myImg/021.jpg","myImg/022.jpg","myImg/023.jpg");
//要取幾張來播放
var playImg = new Array(3);
//目前播放到第幾張
var nowIndex=0;
//從allImg中取出N張放到myImg裡面
for(var i=0;i<playImg.length;i++){
playImg[i] = myImg[Math.ceil(Math.random()*myImg.length-1)];
}

function showImg(){
document.getElementById("my_div").innerHTML = "<img src="+playImg[nowIndex]+">";
//若nowIndex+1後>=playImg的長度，nowIndex重0開始；否則加1
nowIndex = (nowIndex+1)>= playImg.length?0:nowIndex+1;

}
//設定每2秒執行一次showImg()
setInterval("showImg()",5000);
//-->
</script>