如何使用javascript计算文件的md5哈希值
问题描述：
有没有办法在使用Javascript上传到服务器之前计算文件的MD5哈希？
Is there a way to calculate the MD5 hash of a file before the upload to the server using Javascript?
答
MD5算法有 JS实施，旧浏览器一般无法读取文件来自本地文件系统。
我在2009年写过。那么新浏览器呢？
I wrote that in 2009. So what about new browsers?
使用支持 FileAPI 的浏览器，您*可以*阅读内容文件 - 用户必须选择它，使用< input> 元素或拖放。截至2013年1月，主流浏览器如何叠加：
With a browser that supports the FileAPI, you *can * read the contents of a file - the user has to have selected it, either with an <input> element or drag-and-drop. As of Jan 2013, here's how the major browsers stack up:
- FF 3.6支持 FileReader ，FF4支持更多基于文件的功能
- Chrome已支持FileAPI，因为版本7.0.517.41
- Internet Explorer 10有部分 FileAPI支持
- Opera 11.10 对FileAPI的部分支持
- Safari - 我找不到一个好的官方来源，但是这个网站建议从5.1获得部分支持，完全支持6.0 。另一篇文章报道了旧版Safari版本的一些不一致
- FF 3.6 supports FileReader, FF4 supports even more file based functionality
- Chrome has supported the FileAPI since version 7.0.517.41
- Internet Explorer 10 has partial FileAPI support
- Opera 11.10 has partial support for FileAPI
- Safari - I couldn't find a good official source for this, but this site suggests partial support from 5.1, full support for 6.0. Another article reports some inconsistencies with the older Safari versions