I’m wondering if it is possible, to upload a file from the local Computer to a page, without uploading it to a webserver first and then download it from there with ajax.
Can this work with just Javascript & Google Chrome, or must I use flash or something like that?
You must go to the server first. I suppose it might be possible to do a temporary upload to a page but for anything permanent you would need to use a webserver and server side code. All of this can be done in javascript (but would recommend jQuery to make your life easier) and a server side scripting language such as PHP or ASP.