Accept string

An accept string can be a combination of the following values, separated by comma.

Value	Description
file_extension	Specify the file extension(s) (e.g: .gif, .jpg, .png, .doc)
audio/*	All sound files
video/*	All video files
image/*	All image files

For example:

.pdf,.xls

image/*,.pdf,.xls

audio/*

audio/*,video/*