if a user choose a file from his dropbox account with dropbox chooser , how can i save this file to my dropbox automatically
You seem to be asking two separate things; how to save a file to your Dropbox from a share link, and how someone using the Chooser can send you a file. What is it that you actually need to do?
If you're viewing a share link and you want to save the file to your Dropbox, click the down arrow on the Download button and select Save to my Dropbox.
but i want that when someone share a link in my website with my dropbox app which i linked with dropbox chooser, that shared link/file will automatically be saved to my dropbox account.
If I do this, will the person who shared the dropbox file with me lose it? I don't want to move the file from their dropbox, but I want to put a copy on mine from a shared file.
@jade2 No, accessing a file via a shared link does not remove it from the owner's account.