图片轮换问题

[jc15271149]

//图片轮换
var a = 0 ;
var xmlDoc;
function loadxml(path)
{
xmlDoc = new ActiveXObject("Microsoft.XMLDOM");
xmlDoc.async = false;
xmlDoc.load(path);
}
loadxml("test.xml");
function changeImage()
{
var ad = xmlDoc.getElementsByTagName("ad")[0];
if(a == ad.childNodes.length)
{
a=0;
}
var path = ad.childNodes[a].getAttribute("path");
var url = ad.childNodes[a].text;
var image1 = document.getElementById("image1");
image1.src = path;
image1.onclick = function(){location.href =url;};
a+=1;
setTimeout("changeImage()",2000);
}
changeImage();

<img id="image1" src="image/64_jpg.jpg" style="width: 110px; height: 88px" />
<input id="Button1" type="button" value="button" onclick="changeImage()"/>

<?xml version="1.0" encoding="gb2312"?>
<ad>
<NetEasy path="image/64_jpg.jpg">http://www.163.com</NetEasy>
<sina path="image/lining.jpg">http://www.sina.com.cn</sina>
<sohu path="image/Image00045.jpg">http://www.sohu.com</sohu>
</ad>

页面第一次加载时提示有错误:image1 对象为空,图片不轮换
然后点按钮执行则可以实现轮换
请各位帮小弟看一下,谢谢

[meizz]

有HTML代码里 changeImage() 函数的调用放在 <img id="image1" 元素之后。

[jc15271149]

thanks