Anyone know how to get accept working in Edge?
<input type="file" accept=".csv">
Works fine in Chrome 44, Firefox 39, IE 11, Opera 31.
Also tried
<input type="file" accept=".csv,text/csv">
As @mparizeau reported, @JoeHealy's answr is about HTTP Accept header, which is not what the question is about.
To answer the question: at the moment, Edge does not support accept on <input type="file" />.
There used to be a bug tracker here, now it's just a SO redirected search -_-. Anyway, with the upcoming new Microsft Edge (Chromium) this issue will be resolved.