Used to be that the File upload Input box was seriously limited. It used to be very frustrating to deal with it.
In HTML5, there was a major improvement to the File chooser, and there is a Javascript API that lets you do advanced querying of file attributes and filtering.
https://www.html5rocks.com/en/tutorials/file/dndfiles/ However, this means that you will have to upload the files using Javascript. It's more complicated to implement than dropping a control on an HTML page. I believe I have seen someone create an
angular directive that allows you to drop a HTML tag in an HTML page that supports more features than the standard file upload (and if you are not using angular and didn't understand a
word of the preceding line, don't worry about it :lol:)
Obviously, this won't work if your user has disabled Javascript. Most websites will provide a feature rich uploader that works only when Javascript is enabled, and fall back to the standard uploader when Javascript is disabled.