I'm putting this here because I don't really know where would be best, if I could pick a language-categorised solution I probably wouldn't be asking atall...I don't need a solution so much as a pointer.
How do you get a file from a user's computer to a server, from a browser? I'm thinking the multitude of sites that do this: Browse > Upload > Image Sent for "Checking" >(some time layer)> Image appears on site.
How does the very first bit work? Javascript frontend to a SS backend? A binary post request initialised by JavaScript? How does it get past the security on browsers like Firefox? I found out by accident that I can view all my local files (if I know where they are) in Internet Explorer, but thats another topic entirely.
Any ideas?