已验证的php联系表单中的代码错误

我编码了一个联系我们页面并验证它。我想要的是，当用户单击发送按钮时，信息应该首先验证，然后向给定的硬编码电子邮件地址发送电子邮件。我面临一个问题，不知道为什么我的编码不起作用，验证很好，但当我单击提交按钮时，它不会显示任何关于电子邮件和不发送电子邮件的成功消息。请帮忙，这是我的代码：

<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
                        <label>Your Name: * </label>
                        <span style="color:#F00;" class="error"><?php echo $nameErr;?></span>
                        <input type="text" name="name" placeholder="Noman" width="100px;">
                        <label>Email Id: * </label>
                        <span style="color:#F00;" class="error"><?php echo $emailErr;?></span>
                        <input type="text" name="email" placeholder="yourname@gmail.com">
                        <label>Contact Number (Optional): </label>
                        <span style="color:#F00;" class="error"><?php echo $contactErr;?></span>
                        <input type="text" name="contact" placeholder="0312-1234567">
                        <label>  Website URL (Optional):</label>
                        <span style="color:#F00;" class="error"><?php echo $websiteErr;?></span>
                        <input type="text" name="website" placeholder="www.yoursite.com">
                        <label>  Message: * </label>
                        <span style="color:#F00;" class="error"><?php echo $messageErr;?></span>
                        <textarea name="message" rows="10" cols="10" placeholder="Message"></textarea>
                        <input type="submit" name="submit" value="Submit" id="submit">      
                    </form> 

这是我的php代码

<?php
                         function test_input($data) {
                          $data = trim($data);
                          $data = stripslashes($data);
                          $data = htmlspecialchars($data);
                          return $data;
                        }
                         $name= $email= $contact= $website= $message="";                            
                        $nameErr = $emailErr = $contactErr = $websiteErr = $messageErr = "";
                          if ($_SERVER["REQUEST_METHOD"] == "POST")
                          {                           
                          if (empty($_POST["name"])) {
                            $nameErr = "Name is required";
                          } else {
                            $name = test_input($_POST["name"]);
                            if (!preg_match("/^[a-zA-Z ]*$/",$name)) {
                              $nameErr = "Only letters and white space allowed"; 
                            }
                          }
                          if (empty($_POST["email"])) {
                            $emailErr = "Email is required";
                          } else {
                            $email = test_input($_POST["email"]);
                            if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
                                  $emailErr = "Invalid email format"; 
                                }
                          }
                          if (empty($_POST["contact"])) {
                            $contact = "";
                          } else {
                            $contact = test_input($_POST["contact"]);
                          if(!is_numeric($contact)){
                              $contactErr="Please enter valid mobile number";
                            }
                            else if(strlen($contact) != 11) {
                            $contactErr="Please enter valid mobile number";
                            }
                          }
                          if (empty($_POST["website"])) {
                            $website = "";
                          } else {
                            $website = test_input($_POST["website"]);
                             if (!preg_match( "/'b(?:(?:https?|ftp):'/'/|www'.)[-a-z0-9+&@#'/%?=~_|!:,.;]*[-a-z0-9+&@#'/%=~_|]/i",$website)) {
                                  $websiteErr = "Invalid URL"; 
                                }
                          }
                          if (empty($_POST["message"])) {
                            $messageErr = "Message is required";
                          } else {
                            $message = test_input($_POST["message"]);
                          }
                        }
                        $from = $_POST["email"]; // sender
                        $subject = $_POST["name"];
                        $message = $_POST["message"];
                        // message lines should not exceed 70 characters (PHP rule), so wrap it
                        $message = wordwrap($message, 200);
                        // send mail
                        mail("abc@gmail.com",$subject,$message,"From: $email'n");
                        echo "Thank you for sending us feedback";

                        ?>