鼠标实现图片翻转的网页效果

<script language="Javascript">
<!--

button1up=new Image(200,180);
button1up.src="http://www.ob1000.com/images/face/image21.gif";
//鼠标为UP状态时图片大小和图片
button1down=new Image(200,180);
button1down.src="http://www.ob1000.com/images/face/image21.gif";
//鼠标为down状态时图片大小和图片
//more javascript from http://ob1000.com
//-->
</script>

<a href="http://www.ob1000.com" onmouseover="button1.src=button1up.src" onmouseout="button1.src=button1down.src"><img name="button1" src="http://www.ob1000.com/images/face/image21.gif" width=200 height=180 border=0 onload="return imgzoom(this,600);" onclick="javascript:window.open(this.src);" style="cursor:pointer;"/></a>