Source: http://stackoverflow.com/questions/364946/how-to-make-pdf-file-downloadable-in-html-link "[...]run some sanity checks on the "file" variable to prevent people from stealing your files such as don't accept file extensions, add .pdf to the value."

php server for pdf anchors

<a href="pdf_server.php?file=pdffilename">Download my pdf</a>


// pdf_server.php

header("Content-Type: application/octet-stream");

$file = $_GET["file"] .".pdf";
header("Content-Disposition: attachment; filename=" . urlencode($file));   
header("Content-Type: application/force-download");
header("Content-Type: application/octet-stream");
header("Content-Type: application/download");
header("Content-Description: File Transfer");            
header("Content-Length: " . filesize($file));
flush(); // this doesn't really matter.
$fp = fopen($file, "r");
while (!feof($fp))
{
    echo fread($fp, 65536);
    flush(); // this is essential for large downloads
} 
fclose($fp);