Required fields in php email form

We have a problem with our web site form getting submitted blank or just a couple of fields.
I would like to make 'required' the fields 'email, name and telephone'.
I thought 'email' was being checked in the code below but it's not.
I have tried all sorts by surfing the web and adding/changing code but not found the solution.

This is the form back to it's original (working) state..
Any ideas?
Thank you

[CODE]
<?php

$my_email = "xxxx@xxxxx.com";

$continue = "/";

$errors = array();

// Remove $_COOKIE elements from $_REQUEST.

if(count($_COOKIE)){foreach(array_keys($_COOKIE) as $value){unset($_REQUEST[$value]);}}

// Check all fields for an email header.

function recursive_array_check_header($element_value)
{

global $set;

if(!is_array($element_value)){if(preg_match("/(%0A|%0D|\n+|\r+)(content-type:|to:|cc:|bcc:)/i",$element_value)){$set = 1;}}
else
{

foreach($element_value as $value){if($set){break;} recursive_array_check_header($value);}

}

}

recursive_array_check_header($_REQUEST);

if($set){$errors[] = "You cannot send an email header";}

unset($set);

// Validate email field.

if(isset($_REQUEST['email']) && !empty($_REQUEST['email']))
{

if(preg_match("/(%0A|%0D|\n+|\r+|:)/i",$_REQUEST['email'])){$errors[] = "Email address may not contain a new line or a colon";}

$_REQUEST['email'] = trim($_REQUEST['email']);

if(substr_count($_REQUEST['email'],"@") != 1 || stristr($_REQUEST['email']," ")){$errors[] = "Email address is invalid";}else{$exploded_email = explode("@",$_REQUEST['email']);if(empty($exploded_email[1]) || strlen($exploded_email[0]) > 64 || empty($exploded_email[1])){$errors[] = "Email address is invalid";}else{if(substr_count($exploded_email[0],".") == 0){$errors[] = "Email address is invalid";}else{$exploded_domain = explode(".",$exploded_email[1]);if(in_array("",$exploded_domain)){$errors[] = "Email address is invalid";}else{foreach($exploded_domain as $value){if(strlen($value) > 63 || !preg_match('/^[a-z0-9-]+$/i',$value)){$errors[] = "Email address is invalid"; break;}}}}}}

}

// Check referrer is from same site.

if(!(isset($_SERVER['HTTP_REFERER']) && !empty($_SERVER['HTTP_REFERER']) && stristr($_SERVER['HTTP_REFERER'],$_SERVER['HTTP_HOST']))){$errors[] = "You must enable referrer logging to use the form";}

// Check for a blank form.

function recursive_array_check_blank($element_value)
{

global $set;

if(!is_array($element_value)){if(!empty($element_value)){$set = 1;}}
else
{

foreach($element_value as $value){if($set){break;} recursive_array_check_blank($value);}

}

}

recursive_array_check_blank($_REQUEST);

if(!$set){$errors[] = "You cannot send a blank form";}

unset($set);

// Display any errors and exit if errors exist.

if(count($errors)){foreach($errors as $value){print "$value<br>";} exit;}

if(!defined("PHP_EOL")){define("PHP_EOL", strtoupper(substr(PHP_OS,0,3) == "WIN") ? "\r\n" : "\n");}

// Build message.

function build_message($request_input){if(!isset($message_output)){$message_output ="";}if(!is_array($request_input)){$message_output = $request_input;}else{foreach($request_input as $key => $value){if(!empty($value)){if(!is_numeric($key)){$message_output .= str_replace("_"," ",ucfirst($key)).": ".build_message($value).PHP_EOL.PHP_EOL;}else{$message_output .= build_message($value).", ";}}}}return rtrim($message_output,", ");}

$message = build_message($_REQUEST);

$message = $message . PHP_EOL.PHP_EOL."-- ".PHP_EOL."";

$message = stripslashes($message);

$subject = "Free Consultation Request";

$headers = "From: " . $_REQUEST['email'];

mail($my_email,$subject,$message,$headers);


?>
[CODE]

Im not sure if i got what you mean but if this helps here is what i have. This validates every field that is in this line of space

PHP Code:

---

    // validation expected data exists
    if(!isset($_POST['first_name']) ||
        !isset($_POST['last_name']) ||
        !isset($_POST['email']) ||
        //!isset($_POST['telephone']) ||
        !isset($_POST['comments'])) {
        died('We are sorry, but there appears to be a problem with the information you submitted.');      
    } 


---

you can add and remove from that i hope it helps

Code:

---

if(isset($_POST['email'])) {
  $email_to = "email.com";
    $email_subject = "Lights On In Heaven";
 function died($error) {
        // your error code can go here
        echo "We are very sorry, but there were error(s) found with the information you submitted. ";
        echo "These errors appear below.<br /><br />";
        echo $error."<br /><br />";
        echo "Please go back and fix these errors.<br /><br />";
        die();
    }

    // validation expected data exists
    if(!isset($_POST['first_name']) ||
        !isset($_POST['last_name']) ||
        !isset($_POST['email']) ||
        //!isset($_POST['telephone']) ||
        !isset($_POST['comments'])) {
        died('We are sorry, but there appears to be a problem with the information you submitted.');     
    }

    $first_name = $_POST['first_name']; // required
    $last_name = $_POST['last_name']; // required
    $email_from = $_POST['email']; // required
    $telephone = $_POST['telephone']; // not required
    $comments = $_POST['comments']; // required
   
    $error_message = "";
    $email_exp = '/^[A-Za-z0-9._%-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,4}$/';

  if(!preg_match($email_exp,$email_from)) {
    $error_message .= 'The Email Address you entered does not appear to be valid.<br />';
  }
    $string_exp = "/^[A-Za-z .'-]+$/";
  if(!preg_match($string_exp,$first_name)) {
    $error_message .= 'The First Name you entered does not appear to be valid.<br />';
  }
  if(!preg_match($string_exp,$last_name)) {
    $error_message .= 'The Last Name you entered does not appear to be valid.<br />';
  }
  if(strlen($comments) < 2) {
    $error_message .= 'The Comments you entered do not appear to be valid.<br />';
  }
  if(strlen($error_message) > 0) {
    died($error_message);
  }
    $email_message = "";
   
    function clean_string($string) {
      $bad = array("content-type","bcc:","to:","cc:","href");
      return str_replace($bad,"",$string);
    }

    $email_message .= "".clean_string($comments)."\n\n";
    $email_message .= "First Name: ".clean_string($first_name)."\n";
    $email_message .= "Last Name: ".clean_string($last_name)."\n";
    $email_message .= "Email: ".clean_string($email_from)."\n";
    $email_message .= "Telephone: ".clean_string($telephone)."\n";
   
   
// create email headers
$headers = 'From: '.$email_from."\r\n".
'Reply-To: '.$email_from."\r\n" .
'X-Mailer: PHP/' . phpversion();
@mail($email_to, $email_subject, $email_message, $headers);
?>
 
<!-- include your own success html here -->
 
Thank you for contacting us. We will be in touch with you very soon.
 
<?php
}
?>

---