兼容IE6/7的Data-Uri背景图片+css Sprite的mhtml解决方案

/*
Content-Type: multipart/related; boundary="_"
--_
Content-Location:mhtml.jpg
Content-Transfer-Encoding:base64

[img:data-uri]
*/
#tabs{background:url(data:image/jpeg;base64,[img:data-uri]);}
#tabs{*background:expression(function(links){
    return 'url(mhtml:'+links[links.length-1].getAttribute('href',4)+'!mhtml.jpg)';
}(document.getElementsByTagName('link')));

注：[img:data-uri]是base64位的图片data