my contact form mails me blank values when clicked send

[mastrek]

When this form gets submitted I receive an email which have all the values as blank please help me.This is my html file in which I am accepting name, email, and message as input.\[code\]<form id="form" method="post" action="contact.php" > <fieldset> <label><input type="text" value="http://stackoverflow.com/questions/14032487/Name" onBlur="if(this.valuehttp://stackoverflow.com/questions/14032487/=='') this.value='http://stackoverflow.com/questions/14032487/Name'" onFocus="if(this.value http://stackoverflow.com/questions/14032487/=='Name' ) this.value=''"></label> <label><input type="text" value="http://stackoverflow.com/questions/14032487/Email" onBlur="if(this.valuehttp://stackoverflow.com/questions/14032487/=='') this.value='http://stackoverflow.com/questions/14032487/Email'" onFocus="if(this.value http://stackoverflow.com/questions/14032487/=='Email' ) this.value=''"></label> <label><textarea onBlur="if(this.valuehttp://stackoverflow.com/questions/14032487/==''){this.value='http://stackoverflow.com/questions/14032487/Message'}" onFocus="if(this.valuehttp://stackoverflow.com/questions/14032487/=='Message'){this.value=''}">Message</textarea></label><br> <<a href="http://stackoverflow.com/questions/14032487/#" class="button" onClick="document.getElementById('form').submit()">Send</a></div> </fieldset> </form> \[/code\]php file:in php file I want to email all the details on id [email protected].\[code\]<?php$field_name = $_POST['Name'];$field_email = $_POST['Email'];$field_message = $_POST['Message'];$mail_to = '[email protected]';$subject = 'Message from a site visitor '.$field_name;$body_message = 'From: '.$field_name."\n";$body_message .= 'E-mail: '.$field_email."\n";$body_message .= 'Message: '.$field_message;$headers = 'From: '.$field_email."\r\n";$headers .= 'Reply-To: '.$field_email."\r\n";$mail_status = mail($mail_to, $subject, $body_message, $headers);if ($mail_status) { ?> <script language="javascript" type="text/javascript"> alert('Thank you for the message. We will contact you shortly.'); window.location = 'contacts.html'; </script><?php}else { ?> <script language="javascript" type="text/javascript"> alert('Message failed. Please try again.'); window.location = 'contacts.html'; </script><?php}?>\[/code\]How do I fix this?