页面的背景图片向下移动

在< body >之后插入下列代码,则会出现背景图片向下移动。

CODE:

<script language="JavaScript">
<!--
var backgroundOffset = 0;
var bgObject = eval('document.body');
function scrollBG(maxSize) {
backgroundOffset = backgroundOffset + 1;
if (backgroundOffset > maxSize) backgroundOffset = 0;
bgObject.style.backgroundPosition = "0 " + backgroundOffset;
}
var ScrollTimer = window.setInterval("scrollBG(307)" 64);

-->
</script>