Accept a form input, and save to a data file on the server.

form_to_csv.php

<?php
//form hamdler to save to CSV

//un-comment the next two lines to troubleshoot
//ini_set('display_errors',1);
//error_reporting(E_ALL);

//MAIN CONFIGURATION
//where the data will be saved -- outside of the Web server's root folder
//this folder 'csv' must exist, and must be set to allow the server to
//write to it. ask your hosting provider if you're unsure.
$data_file = dirname(dirname(__FILE__)) . '/csv/report.csv';
$thanks_page = 'http://www.example.com/index.html';

//LIBRARY CODE, DON'T EDIT
function clean($mxdInput){
  //recursive function for multidimensional arrays
  if(is_string($mxdInput)) return trim(strip_tags($mxdInput));
  $out = array();
  foreach($mxdInput as $k=>$v){
    $out[$k] = clean($v);
  }
  return $out;
}
function humanize($strFieldName){
  return ucwords(str_replace('_',' ',$strFieldName));
}
$errors = $values = array();
if(isset($_POST['_submit'])){
  $fields = clean($_POST);
  $headers = array();
  foreach($fields as $header => $value){
    //add the data only if it's not "private"
    if(substr($k,0,1) != '_'){
      $headers[] = '"' . addslashes(humanize($header)) . '"';
      $values[] = '"' . addslashes($value) . '"';
    }
  }
  if(!file_exists($data_file)){
    file_put_contents($data_file,implode(',',$headers) . "\n");
  }
  file_put_contents($data_file, implode(',',$values) . "\n", FILE_APPEND);
  header('Location: ' . $thanks_page);
}
?>