PHP Content-Disposition: attachment / Content-Type

Question

just a little question (PHP): I'm using

header('Content-Disposition: attachment; filename="downloaded.pdf"');
readfile('test.pdf');

to download a file under another filename. But in every script-example of this, there was "header('Content-type: application/pdf');" before this 2 lines in the code. I deletet the content-type-line and it still works fine. Do i need the missing line, when i just want to change the name of the downloaded file? Because therre are many filetypes, that can be downloaded in my website and so i would have to read the content-type before...

Thanks in advance for a short but understandable answer :)

Answer 1

Yes, you need it.

If you don't supply it, then PHP will default to outputting Content-Type: text/html which will cause problems (at the very least) for browsers that only handle inline content (such as Mobile Safari).