Lo que pasa es que son varios archivos ... 
 
Este es el HTML   Código HTML:
 <!--
/************* Ajax Contact Form 1.0 *****************************/
/*
Released by AwesomePHP.com, under the GPL License, a
copy of it should be attached to the zip file, or
you can view it on http://AwesomePHP.com/gpl.txt
*/
/************* Ajax Contact Form 1.0 *****************************/
-->
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Ajax Enabled PHP Contact Form</title>
<style type="text/css">
td
{	
	border:1px solid gray;
	font-size:12px;
}
.header
{
	background-color:#CCCCCC;
	font-size:20px;
}
.error
{
	background-color:#FFBFBF;
	color:#FF0000;
	font-size:14px;
}
*
{
	font-family:Verdana, Arial, Helvetica, sans-serif;
}
textarea,.textbox
{
	width:100%;
	border:1px solid gray;
}
</style>
</head>
<script type="text/javascript" src="formProcess.js"></script>
<body>
<form name="contact" id="contact" method="post" action="contact.html" style="display:inline;">
  <table width="70%"  border="0" align="center" cellpadding="5" cellspacing="0">
    <tr>
      <td colspan="2" class="header"><div align="center">Contact Form: </div></td>
    </tr>
    <tr id="errorSpanTR" style="display:none;">
      <td colspan="2" class="error"><span id="errorSpan"></span></td>
    </tr>
    <tr>
      <td width="50%">Please enter your name: </td>
      <td width="50%"><input name="customerName" type="text" id="customerName" class="textbox"></td>
    </tr>
    <tr>
      <td width="50%">Please enter your email: </td>
      <td width="50%"><input name="customerEmail" type="text" id="customerEmail" class="textbox"></td>
    </tr>
    <tr>
      <td width="50%">Please enter your telephone: </td>
      <td width="50%"><input name="customerPhone" type="text" id="customerPhone" class="textbox"></td>
    </tr>
    <tr>
      <td width="50%">What should we use to call you back: </td>
      <td width="50%"><input name="callBackMethod" type="radio" value="Phone">
        Phone 
          <input name="callBackMethod" type="radio" value="Email" checked> 
          E-Mail
</td>
    </tr>
    <tr>
      <td width="50%">What time should we call you back (if by phone):</td>
      <td width="50%"><select name="callBackHour" id="callBackHour">
        <option value="1">1</option>
        <option value="2">2</option>
        <option value="3" selected>3</option>
        <option value="4">4</option>
        <option value="5">5</option>
        <option value="6">6</option>
        <option value="7">7</option>
        <option value="8">8</option>
        <option value="9">9</option>
        <option value="10">10</option>
        <option value="11">11</option>
        <option value="12">12</option>
      </select>
        : 
        <select name="callBackMinutes" id="callBackMinutes">
          <option value="00">00</option>
          <option value="05">05</option>
          <option value="10">10</option>
          <option value="15" selected>15</option>
          <option value="20">20</option>
          <option value="25">25</option>
          <option value="30">30</option>
          <option value="35">35</option>
          <option value="40">40</option>
          <option value="45">45</option>
          <option value="50">50</option>
          <option value="55">55</option>
                        </select> <select name="callBackHoursSpan" id="callBackHoursSpan">
                          <option value="AM">AM</option>
                          <option value="PM" selected>PM</option>
                                                                        </select> </td>
    </tr>
    <tr>
      <td>What department should call you back: </td>
      <td width="50%"><select name="departmentInterested" id="departmentInterested">
        <option value="Support" selected>Support</option>
        <option value="Billing">Billing</option>
        <option value="Complaints">Complaints</option>
      </select></td>
    </tr>
    <tr>
      <td>What services are you interested in: </td>
      <td width="50%"><input name="serverInterested[]" type="checkbox" id="serverInterested[]" value="WebDesign">
      Web Design 
        <input name="serverInterested[]" type="checkbox" id="serverInterested[]" value="WebHosting">
Web Hosting 
<input name="serverInterested[]" type="checkbox" id="serverInterested[]" value="WebProgramming"> 
Web Programming
</td>
    </tr>
    <tr>
      <td colspan="2">Please enter your message: </td>
    </tr>
    <tr>
      <td colspan="2"><div align="center">
        <textarea name="customerMessage" id="customerMessage"></textarea>
      </div></td>
    </tr>
    <tr>
      <td colspan="2"><div align="center">
        <input type="button" name="Button" value="Send This Information" onClick="submitForm();">
      </div></td>
    </tr>
  </table>
</form>
</body>
</html>  ESTE ES EL PHP   
Código PHP:
Ver original<?php
/************* Ajax Contact Form 1.0 *****************************/
/*
Released by AwesomePHP.com, under the GPL License, a
copy of it should be attached to the zip file, or
you can view it on http://AwesomePHP.com/gpl.txt
*/
/************* Ajax Contact Form 1.0 *****************************/
 
/* Emails to send admins (comma separated) */
 
/* Site Name */
$siteName = 'Ajax Contact Form Demo';
 
/* Email Subject for admins */
$subject = 'You\'v Got Mail';
 
/* Email subject for users making the contact*/
$subjectUser = 'ESTO ES UN FORMULARIO DE PRUEBA CON AJAX';
 
/* Email message to send users making the contact*/
$userMessage = "Esto es un correo de confirmacion de que usted nos ha escrito";
/* Email message add-on if also sending variables (information) */
$userMessageVariables = 
"Here is the information you sent us:\n<br />
-------------------------------------------------\n<br />";
 
/* Thank you message on page */
$thankYouNote = 'Su mensaje ha sido enviado gracias.';
 
/* Send Thank you Email to sender */
$sendThankYou = true;
 
/* Include form variables in Thank you Email */
$sendVariable = true;
 
/* Email field to send thank you to */
$thankYouEmailField = 'customerEmail';
 
/* Do you want to require any fields ?*/
$REQUIRE[] = 'customerName';
$REQUIRE[] = 'customerMessage';
 
/* Email fields to check for validation */
/*
If you want an email field to be required, it should
also be on the REQUIRE list
*/
$EMAILFIELD[] = 'customerEmail';
 
 
?>
  
Pero hay otros archivos en .js y .txt