我的表单的PHP脚本的Noob问题

提前感谢所有人：

当我测试表单页面时，它加载了一个错误"undefined variable lines…."，对应于前四个if/else语句的$myname和$email。

当我将第一个endif移到脚本底部时，未定义的变量会消失，但当我没有正确填写表单时，错误消息将不再显示，并且当我这样做时，"谢谢填写表单"消息也不再显示：（

此外，当我在顶部有第一个endif时，在我触摸表单之前，错误消息"你的名字必须采用格式：Last，first"answers"你的电子邮件必须采用正确的格式"就已经出现了。

好的，这是我在一个单独的文件上的表单和PHP脚本：

<?php if (isset($msg)) { echo '<div id = "thanks"/><p>', $msg , '</p></div>'; } ?>
<form id="myform" name="theform" class="group" action="<?php echo $_SERVER['PHP_SELF'] ?>" method="POST">
<span id="firstname"> Name (Last, First):</span> <span id="firstnamefield">
<input type="text" name="myname" size="50" value:"<?php if (isset($myname)) {echo $myname;} ?>"/></span>
<?php if (isset($err_myname)) { echo '<div id = "error"/><p>', $err_myname , '</p></div>'; } ?>
<?php if (isset($err_namematch)) { echo '<div id = "namematch"/><p>', $err_namematch , '</p></div>'; } ?>

<span id="mail">Email:</span> <span id="emailfield"><input type="text" name="email" value="<?php if (isset($email)) {echo $email;} ?>"/></span>
<?php if (isset($err_email)) { echo '<div id = "emailerror"/><p>', $err_email , '</p></div>'; } ?>
<?php if (isset($err_patternmatch)) { echo '<div id = "emailmatch"/><p>', $err_patternmatch , '</p></div>'; } ?>

<span id="telephone">Phone:</span><span id="phonefield"><input type="text" name="phone" value="<?php if (isset($phone)) {echo $phone;} ?>"/></span>

<span id="sub"><input type="image" name="action" value="submit"   src="images/submit.png" alt="Submit" /></span>
</form> 

这是我的PHP文件：

<?php 
if (($_SERVER['REQUEST_METHOD'] == 'POST') && (!empty($_POST['action']))): 
endif; //form submitted   
    if (isset($_POST['myname'])) { $myname = $_POST['myname']; } 
    if (isset($_POST['phone'])) {$phone = $_POST['phone']; }  
    if (isset($_POST['email'])) {$email = $_POST['email']; }  

    $formerrors = false;
    if ($myname ===''):
      $err_myname = "*Sorry, your name is a required field";
      $formerrors = true;
    endif; //Input Field Empty

    if ($email ===''):
      $err_email = "*Sorry, your email is a required field";
      $formerrors = true;
    endif; //Input Field Empty

   if ( !(preg_match('/^([0-9a-zA-Z]([-'.'w]*[0-9a-zA-Z])*@([0-9a-zA-Z][-'w]*[0-9a- zA-Z]'.)+[a-zA-Z]{2,9})$/', $email)) ):
     $err_patternmatch = "*Your email must be in the correct format";
     $formerrors = true;
   endif; //Input Must Match Proper Format

   if ( !(preg_match('/[A-Za-z]+, [A-Za-z]+/', $myname))):
     $err_namematch = "*Your name must be in the format: Last, First";
     $formerrors =true;
   endif; //Input Must Match Proper Format

   if (!($formerrors)):
     $to  =  "test1234@yahoo.com"; 
     $subject  =  "From $myname --Postcard Landing Page";
     $message  = "You have a new lead.";
     $replyto  =  "From: $email 'r'n".
             "Reply-To: donotreply@domain.com 'r'n";
    if (mail($to,$subject,$message)):
         $msg = "Thank you for filling out the form!";
    else:
         $msg =  "Problem sending message";
    endif; // mail form data                    
    endif; // Check for For Errors

?>