&action=download

<?php
ob_start();
$fields = array('name','emailaddress','message');
$host = 'localhost';
$dbname = 'mydb';
$user = 'myuser';
$pwd = 'mypwd';

if (isset($_REQUEST['action'])):
    switch (strtolower($_REQUEST['action'])):
        case 'save':
            savedata();
            showthankyoupage();
            break;
        case 'download':
            downloaddata();
            break;
    endswitch;    
else:
    displayform();
endif;

function connectdb(){
    global $host, $dbname, $user, $pwd;
    global $pdo;
    $pdo = new PDO(
        "mysql:host=$hose;dbname=$dbname",
        $user,
        $pwd
        array(PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES utf8"
    );
}
function savedata(){
    global $fields;    
    foreach($fields as $field):
        $placeholder[] = '?';
        $params[] = empty($_REQUEST[$field]) ? '' : trim($_REQUEST[$field];
    endforeach;
    connectdb();
    global $pdo;
    $s = $pdo->prepare("Insert into formdata (". implode(',', $fields) . ") VALUES (". implode(',',$placeholder) .")");
    $pdo->execute($params);
    return true;
}

function showthankyoupage(){
    ob_end_clean();
    include 'thankyoupagetemplate.php';
    exit;
}

function downloaddata(){
    global $fields;
    connectdb();
    global $pdo;
    $s = $pdo->prepare("select * from formdata");
    $s->execute();
    $output = <<<OP
<table>
    <thead>
        <tr>
            <th>
OP;
    $output .= implode('</th><th>', $fields);
    $output .= '</th></tr></thead>';
    $output .= '<tbody>';
    while ($row = $s->fetchObject()):
        $inner = array();
        foreach($fields as $field):
            $inner[] = '<td>' . htmlspecialchars($row->$field) . '</td>';
        endforeach;
        $output .= '<tr>' . implode("\n", $inner) . '</tr>';
    endwhile;
    $output .= "</tbody></thead>";
    ob_end_clean();
    header("Content-Disposition: attachment; filename=\"formData.xls\"");
    header("Content-Type: application/vnd.ms-excel");
    echo $output;
}

function displayform(){
    include 'formpage.php';
}
?>