Text file on the fly for user to download using php

Here's the code for generating a text file on the file for user to download.
Make sure you don't have any output before this code, otherwise it will be shown on the downloaded file also.


<php? //Generate text file on the fly

   header("Content-type: text/plain");
   header("Content-Disposition: attachment; filename=test.txt");

   $str="test";

   echo $str;
  
 ?>