As I want to upload a remote FTP link, I removed the red part in submit.php.

if( $can_do_it == 1 AND $this->ipsclass->input['file_url'] AND $this->ipsclass->xss_check_url( $this->ipsclass->input['file_url'] ) )

Now is the problem, does 'xss_check_url' only check the header of the link or also check the file size? If 'xss_check_url' doesn't check the file size and the file size shows wrong after I uploaded an FTP link, is it the problem of the settings of the FTP server? how to set up the FTP server to allow IDM check the file size?

Thanks.

Huh?

xss_check_url checks the actual url. So if you submitted something like

java script:alert(something) it would produce an error. xss_check_url does not check filesizes, headers, or any of that - just the actual ASCII url string.

IDM is not capable of checking the filesize of a remote file via FTP protocol. For http:// links it does an HTTP HEAD request to get the Content-Length header to determine the size of a remote file.

I see. Thanks, bfarber.