When I upload files on Firefox, does it reveal the file location?

If I upload a file to a website, can they see the folder name it was located in, and the path?

2 Answers

Firefox and other major browsers implement a fakepath mechanism:

filename
On getting, return the string "C:\fakepath\" followed by the name of the first file in the list of selected files, if any, or the empty string if the list is empty.

So the site will see something like C:\fakepath\filename.

No, the path to the file (including the directory it is in) is hidden, or truncated. All they will see is the name of the file after /fakepath/filename.