<script>
window.onload = function(){
// 设置定时:
window.setInterval("changeImg()",5000);
}
var i = 1;
function changeImg(){
i++;
// 获得图片的控制权:
if(i > 3){
i=1;
}
var img1 = document.getElementById("img1");
img1.src="../img/"+i+".jpg";
}
</script>
原文:http://blog.51cto.com/13517854/2110617