This is for users who are looking for a way to merge HTML form data with a PDF Form, then output the PDF Form with data populated in it, to a web browser.

This is a pure PHP solution which does NOT require the FDF toolkit. Contributed by www.TUFaT.com

<?php

// the full http path to the PDF form
$form = 'http://my_domain.com/my_pdf_form.pdf';

function create_fdf ($pdffile, $strings, $keys)
{
    $fdf = "%FDF-1.2\n%????\n";
    $fdf .= "1 0 obj \n<< /FDF << /Fields [\n";

    foreach ($strings as $key => $value)
    {
        $key = addcslashes($key, "\n\r\t\\()");
        $value = addcslashes($value, "\n\r\t\\()");
        $fdf .= "<< /T ($key) /V ($value) >> \n";
    }
    foreach ($keys as $key => $value)
    {
        $key = addcslashes($key, "\n\r\t\\()");
        $fdf .= "<< /T ($key) /V /$value >> \n";
    }

    $fdf .= "]\n/F ($pdffile) >>";
    $fdf .= ">>\nendobj\ntrailer\n<<\n";
    $fdf .= "/Root 1 0 R \n\n>>\n";
    $fdf .= "%%EOF";

    return $fdf;
}

// Fill in text fields
$strings = array(
    'date' => '10/17/2004',
    'full_name' => 'Joe Doe',
    'phone_num' => '123-4567',
    'company' => 'ACME Widgets',
    'amount' => 'USD 100.00'
    );

// Fill in check boxes/radio buttons
$keys = array('
    gender' => 'male',//radio button
    'is_adult' => 'Off',//checkbox
    'urgent' => 'On'//checkbox
    );

// Output the PDF form, with form data filled-in
header('Content-type: application/vnd.fdf');
echo create_fdf($form, $strings, $keys);

?>