How can JavaScript get data from a user's computer?

Question

How can Javascript (running from a website on a remote server) access data from a user's local computer? I have access to all the user's computers and they are all using Chrome. The data may be stored in a file, a database, I can even run a webserver on their computers if needed, etc. Is there any way for my users to for example allow my website to access data from JavaScript? (maybe be there is a Chrome setting but I still want their browser to be secure)

Answer 1

As far as I know, you cannot access the files on the user's machine using javascript. This would be a huge security hole. You have to write a client (not web) application (windows app or whatever technology you are using).

Answer 2

this is not possible just using a browser, because as you said yourself it would`t be secure. You can use some kind of plugin which your users have to allow which then can access the local data on the computer.