这两天使用iewatch观察google的网站的时候，发现学到js文件的mime类型为text/javascript，而今天在qq的网站上，使用iewatch发现，有时用text/javascript的，也有使用application/javascript的还有使用appliation/x-javascript的，所有就不太知道这三个mime 类型有什么区别，在google上一搜：
The traditional MIME type for JavaScript programs is
"text/javascript". Another type that has been used is
"application/x-javascript" (the "x" prefix indicates that it is an
experimental, nonstandard type). RFC 4329 standardized the
"text/javascript" type because it is in common use. However, because
JavaScript programs are not really text documents, it marks this type
as obsolete and recommends "application/javascript" (without the "x-")
instead. At the time of this writing, "application/javascript" is not
well supported, however. That might be the reason why
"application/x-javascript" is used by a lot of webpages.
大致意思是：传统的javascript程序的MIME类型是“text/javascript”，其他使用的还有"application/x-javascript"（x前缀表示这是实验性的，不是标准的类型），RFC4329规定了“text/javascript”类型，因为它普遍被使用。然而，javascript程序并不是真正的文本文件，这就表示这个类型已经意味着过时了，而推荐使用"application/javascript"（去除x前缀）。然而，在写程序的时候，"application/javascript"没有很好的支持。这也行就是"application/x-javascript"被使用在很多网页中的原因。