Outputting PHP mail form errors to same page

Outputting PHP mail form errors to same page

This is for a live commercial project so any help is greatly appreciated.
I am relatively new to PHP and jQuery/Javascript so forgive me if most of
what I have already is what you experts would deem... crap :)
My website is HTML only with a contact form that uses a PHP mail form (the
contact form is on an HTML document still).
Using jQuery Validate, I have implemented client-side validation which
works to a level that I am happy with.
I have also implemented server side validation and sanitization within the
PHP form script.
While client and server side validations appear to be working together
correctly, I'm suffering a mental block in how to display error messages
generated by the server side PHP script.
Client slide jQuery validation works fine - I have an error message
container DIV on the contact.html page which displays the correct error
messages; however, for server side - when I hit submit, it goes loads
contact-form.php in the browser and displays the error messages (or
success message) - on a blank page.
What I want is any output error messages from the contact-form.php file to
be displayed in the same error container DIV as the jQuery, without
actually leaving the page.
The reason I am trying to do this is - if the user does not have
javascript enabled, jQuery validator is obviously not going to work - but
I still need the PHP error handling to be just as elegant as the jQuery
handling.
Thank you for taking the time to read and advise.
Here is my code as it stands:
contact-form.php
<?php
$formType = $_POST['formType'] ;
$sender_name = $_POST['name'] ;
$sender_company = $_POST['company'] ;
$sender_email = $_POST['email'] ;
$sender_telephone = $_POST['telephone'] ;
$sender_message = $_POST['message'] ;
// Server Side Validation
// Error Messages
// Name
$errorMsg_Name_Empty = "Please enter your name (cannot be
empty). <br />" ; // isEmpty
$errorMsg_Name_Invalid = "Please your name using valid characters
only. <br />" ; // Contains illegal characters only
// Email
$errorMsg_Email_Invalid = "Please enter a valid e-mail address.
<br />" ;
$errorMsg_Email_Empty = "Please enter your e-mail address
(cannot be empty). <br />" ;
// Telephone
$errorMsg_Telephone_Invalid = "Please enter a valid telephone number." ;
$errorMsg_Telephone_Empty = "Please enter your telephone number
(cannot be empty). <br />" ;
// Message
$errorMsg_Message = "Please enter a message. Your message
should be at least 30 and no more than 3000 characters in length. <br />"
;
// Human
$errorMsg_Human_Incorrect = "You have not answered the simple maths
question correctly! <br />" ;
// Callback Date
$errorMsg_callbackDate = "Please enter a valid date for us to
call you back on, formatted as dd/mm/yyyy (for example: 31/01/2103). <br
/>" ;
// Callback Time
$errorMsg_callbackTime = "Please specify a time you would like us
to call you back. <br />" ;
// Input: Name
if ( $sender_name != "") {
$sender_name = substr(filter_var( $sender_name,
FILTER_SANITIZE_STRING), 0,49) ;
if ( $sender_name == "" ) {
$errors .= $errorMsg_Name_Invalid ;
}
} else {
$errors .= $errorMsg_Name_Empty ;
}
// Input: Company
if ( $sender_company != "") {
$sender_company = substr(filter_var( $sender_company,
FILTER_SANITIZE_STRING),0,49);
}
// Input: Email
if ( $sender_email != "") {
$email_temp = filter_var( $sender_email, FILTER_SANITIZE_EMAIL);
if (!filter_var( $email_temp, FILTER_VALIDATE_EMAIL )) {
$errors .= $errorMsg_Email_Invalid ;
}
} else {
$errors .= $errorMsg_Email_Empty ;
}
// Input: Telephone
if ( $sender_telephone != "") {
$sender_telephone = filter_var($sender_telephone,
FILTER_SANITIZE_NUMBER_INT);
if ( strlen ( $sender_telephone ) < 11 || strlen ( $sender_telephone )
> 12 ) {
$errors .= $errorMsg_Telephone_Invalid ;
}
} else {
$errors .= $errorMsg_Telephone_Empty ;
}
// Input: Message
if ( $sender_message != "") {
$sender_message = filter_var($sender_message, FILTER_SANITIZE_STRING);
if ($sender_message == "") {
$errors .= $errorMsg_Message ;
} elseif ( strlen ($sender_message) < 30 || strlen ($sender_message) >
3000 ) {
$errors .= $errorMsg_Message ;
}
} else {
$errors .= $errorMsg_Message ;
}
// Human
if ($formType == "Message") {
$human = $_POST['human_message'] ;
} elseif ( $formType == "Callback") {
$human = $_POST['human_callback'] ;
} ;
$human_correctAnswer = '12' ;
// Input: Human
if ( $human != $human_correctAnswer) {
$errors .= $errorMsg_Human_Incorrect ;
}
// Callback Specific
// If form type is "Callback", collect time/date input fields.
if ( $formType == "Callback" ) {
$callback_date = $_POST['callback_date'] ;
$callback_time = $_POST['callback_time'] ;
//Callback date
if ( $callback_date != "" ) {
list ($day,$month,$year) = explode ("/" ,$callback_date );
if ( (is_numeric($day)) || (is_numeric($month)) ||
(is_numeric($year)) ) {
if (!checkdate($month, $day, $year))
$errors .= $errorMsg_callbackDate ;
} else {
$errors .= $errorMsg_callbackDate ;
}
} else {
$errors .= $errorMsg_callbackDate ;
} ;
//Callback Time
if ( $callback_time == "" ) {
$errors .= $errorMsg_callbackTime ;
}
}
// END Callback Specific
// If there are no errors - send the form.
if (!$errors) {
$sender_ipAddress = $_SERVER['REMOTE_ADDR'];
$sender_browser = $_SERVER['HTTP_USER_AGENT'];
// E-mail headers
$recipient_email = "hello@mywebsite.com" ;
$headers = "MIME-Version: 1.0" . "\r\n";
$headers .= "Content-type:text/html; charset: utf8" . "\r\n";
$headers .= "From: My Website\r\n";
$headers .= 'Reply-To: no-reply@mywebsite.com' . "\r\n" ;
// Setting the e-mail subject
if ( $formType == "Message" ) {
$subject = "Message from the My website." ;
} else {
$subject = "Callback request from the My website." ;
};
// For database scripting - replace new-line html with carriage return
character - Array
// Placeholders for array
$sender_message_placeholders = array("\n") ;
//Replace Values for array
$sender_message_replaceValues = array("¶") ;
// $sender_message stripped of new-lines, and replaced with
nc-characters.
$sender_message_stripped = str_replace($sender_message_placeholders,
$sender_message_replaceValues, $sender_message) ;
// Writing the e-mail body.
if ( $formType == "Message") {
$emailBody = "
<style type \"text/css\">
body { font-family: Helvetica, Arial ;
font-size: 16px ; line-height: 20px ; color: #5e5e5e }
h1 { font-size: 42px ; line-height:
42px ; color: #c1c1c1 }
div.section { padding: 12px ; margin-bottom:
8px ; background-color: #f7f7f7 ; border: 1px solid #c8c8c8 }
div.part { margin-bottom: 8px ; 1border:
1px solid blue }
div.part:last-child { margin-bottom: 0 }
label { margin: 0 ; font-size: 13px ;
line-height: 20px ; font-weight: bold ; color: #80a553 }
p { margin: 0 }
p.input-field#sender-message { white-space: pre-line }
div#dbImport { color: #a1a1a1!important }
div#dbImport p { font-size: 12px!important ;
line-height: 14px ; white-space: normal!important }
</style>
</head>
<body>
<html>
<h1>Message</h1>
<p class=\"input-field\" style=\"margin-bottom:12px\">A message
has been sent from Mywebsite. The message is as follows:</p>
<div class=\"section\">
<div class=\"part\">
<label>Contact Form Type:</label>
<p class=\"input-field\">$formType</p>
</div>
</div>
<div class=\"section\">
<div class=\"part\">
<label>Name:</label>
<p class=\"input-field\">$sender_name</p>
</div><!-- !.part -->
<div class=\"part\">
<label>Company:</label>
<p class=\"input-field\">$sender_company</p>
</div><!-- !.part -->
<div class=\"part\">
<label>E-mail:</label>
<p class=\"input-field\">$sender_email</p>
</div><!-- !.part -->
<div class=\"part\">
<label>Telephone:</label>
<p class=\"input-field\">$sender_telephone</p>
</div><!-- !.part -->
</div><!-- !.section -->
<div class=\"section\">
<div class=\"part\">
<label>Message:</label>
<p class=\"input-field\"
id=\"sender-message\">$sender_message</p>
</div><!-- !.part -->
</div><!-- !.section -->
<div class=\"section\" id=\"visitor-info\">
<div class=\"part\">
<label>Sender IP Address:</label>
<p class=\"input-field\"><a
href=\"http://network-tools.com/default.asp?prog=express&host=$sender_ipAddress\">$sender_ipAddress</a></p>
</div><!-- !.part -->
<div class=\"part\">
<label>Sender Web Browser:</label>
<p class=\"input-field\">$sender_browser</p>
</div><!-- !.part -->
</div><!-- !.section -->
<div id=\"dbImport\">
<p style=\"font-weight:bold\">IMPORTDB DATA</p>
<p>NAME/COMPANY/EMAIL/TELEPHONE/MESSAGE/CALLBACK-DATE/CALLBACK-TIME</p>
<p>#begin#$sender_name#$sender_company#$sender_email#$sender_telephone#$sender_message_stripped