<body onload='setInterval("changeBG()",1000)'>
<script>
function changeBG()
{
document.body.background=Math.floor(Math.random()*9)+".jpg";
}
</script>
<script>
function changeBG()
{
document.body.background=Math.floor(Math.random()*9)+".jpg";
}
</script>
<script>
function changeBG()
{
//随机显示pic1……pic9十张背景图.
document.body.background="pic"+(Math.floor(Math.random()*9+1)+".jpg"));
}
</script>
<script>
//对图片进行预载.
var arr = new Array();
for(var i=1;i<10;i++)
{
arr[i] = new Image();
arr[i].src = "pic" + i + ".jpg";
}
function changeBG()
{
document.body.background="pic"+(Math.floor(Math.random()*9+1)+".jpg"));
}
</script>