<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<script type="text/javascript">
var time;
window.onload = function(){
time = setTimeout("show()",2000);//设置两秒后开始调用show方法，并用time记住setTimeout的返回值
}
function show(){
var img1 = document.getElementById("img1");
img1.style.display = "block";//将图片设置为显示
clearTimeout(time);//清除原来的setTimeout的设置，可以不写，因为下面有重新赋值
time = window.setTimeout("hide()",2000); //两秒后调用hide()方法隐藏图片，并将time重新赋值。
}
function hide(){
var img1 = document.getElementById("img1");
img1.style.display = "none";//将图片设置为隐藏
clearTimeout(time);//可有可无
time = window.setTimeout("show()",2000);//两秒后调用show()方法显示图片，并将time重新赋值
}
</script>
</head>
<body>
<img src="img3.jpg" id="img1" id="img1">
</body>
</html>
