求教油猴脚本写法

我的脚本

var allLinks, thisLink, addLink;
    allLinks = document.getElementsByTagName('img');
    for (var i = 0; i < allLinks.length; i++) 
	{
    thisLink = allLinks[i];
    if (thisLink.src.match(/\/images\/.+_thumb\.jpg/))
	{
	addLink = document.createElement('a');
	addLink.href = thisLink.src.replace('_thumb.','_original.');
	addLink.innerHTML = 'X';
    thisLink.parentNode.insertBefore(addLink, thisLink);
	}
	}

效果<a href="http://weheartit.com/entry/3390436"><a href="http://whi.s3.prod.lg1x8.simplecdn.net/images/3390436/tumblr_l6jhum7uoZ1qaliy1o1_500_original.jpg?1281889129">X</a><img alt="COMBATBABYxx" class="img" src="http://whi.s3.prod.lg1x8.simplecdn.net/images/3390436/tumblr_l6jhum7uoZ1qaliy1o1_500_thumb.jpg?1281889129" height="200" width="240"></a>

我想要的结果<a href="http://weheartit.com/entry/3390436"><img alt="COMBATBABYxx" class="img" src="http://whi.s3.prod.lg1x8.simplecdn.net/images/3390436/tumblr_l6jhum7uoZ1qaliy1o1_500_thumb.jpg?1281889129" height="200" width="240"></a><a href="http://whi.s3.prod.lg1x8.simplecdn.net/images/3390436/tumblr_l6jhum7uoZ1qaliy1o1_500_original.jpg?1281889129">X</a>

thisLink.parentNode.insertBefore(addLink, thisLink);

应该改成

thisLink.parentNode.parentNode.insertBefore(addLink, thisLink.parentNode.nextSibling);

如果要处理的 img 元素外边不一定套 a 元素的话，最好再加个判断

if(thisLink.parentNode.nodeName.toLowerCase() == 'a') {【代码】}

谢谢啦