How do I automatically upload files via Javascript+HTML?

I'm trying to build a web application that will ask the user for a file and directory on his machine, then upload all the files in the directory with that file's name. So, for example, the user would click on "my_file.doc" and if there's "my_file.xls" and "my_file.pdf" in the same folder, this web app would recognize and try to upload all three files. I got the first part working, so the Javascript (and ActiveX) finds the correct files on the user's machine, but does anybody know how I actually get the browser to upload those files? The ActiveX documentation is severly lacking. Thanks.