现在的问题是，你不能把同样的方式作为普通的文本字段文件中的字段。

The problem is that you can't treat file fields in the same manner as regular text fields.

当你调用 $（'输入'）。VAL（），你得到的文本字段中的实际文本值，但该文件字段，你得到的文件名称 - 而不是文件内容

When you call $('input').val(), you get an actual text value for the text field, but for the file field you get the file name - and not the file contents.

那么你的脚本试图验证文件名的文件，显然，失败。为了让文件验证器，您需要有实际的文件内容传递给脚本成功。

Then your script tries to validate your file name as a file and, apparently, fails. In order for file validator to succeed you need to pass actual file contents to the script.

所以，基本上，你需要异步上传文件到服务器进行所有必要的验证。

So, basically, you need to upload a file asynchronously to the server to perform all the necessary validations.

不幸的是，通过Ajax上传的文件，并不是一个简单的事情。你的基本选项是通过的iFrame 上传文件或 SwfObject的。你可以看看的广泛选择合适的插件用于这一目的here.

Unfortunately, uploading files via Ajax is not quite a trivial thing to do. Your basic options are uploading files via iFrame or swfObject. You can take a look at the broad selection of plugins suitable for this purpose here.

异步文件上传我个人的选择是文件上传的jQuery插件。

My personal choice for asynchronous file upload would be file-uploader jQuery plugin.