So I tried making my own contact form and that kind of worked but I really wanted to add some cool features like telling users when they didn't fill in a required form and telling them when they submitted the form correctly. I got this code from this site. Whenever I click the submit button it takes me to my PHP file link and the page is blank! I want to be able to stay on the same page and have the success/error messages appear not to be redirected. Sorry, I'm a bit new to web development.
BOTH FILES ARE .PHP!!!
Here's the code:
<?php
    if (isset($_POST["submit"])) {
        $name = $_POST['name'];
        $email = $_POST['email'];
        $message = $_POST['message'];
    $subject = $_POST['subject'];
        $from = 'Plugin Request Form'; 
        $to = 'theslimeslayer04@gmail.com'; 
        $subject = 'New Plugin Request';
        $body = "From: $name\n E-Mail: $email\n Subject: $subject\n Message:\n $message";
        // Check if name has been entered
        if (!$_POST['name']) {
            $errName = 'Please enter your name';
        }
        // Check if email has been entered and is valid
        if (!$_POST['email'] || !filter_var($_POST['email'], FILTER_VALIDATE_EMAIL)) {
            $errEmail = 'Please enter a valid email address';
        }
        //Check if message has been entered
        if (!$_POST['message']) {
            $errMessage = 'Please enter your message';
        }
    if(!$_POST['subject']) {
      $errSubject = 'Please enter a subject';
    }
// If there are no errors, send the email
if (!$errName && !$errEmail && !$errMessage && !$errHuman) {
    if (mail ($to, $subject, $body, $from)) {
        $result='<div class="alert alert-success">Thank You! I will be in touch</div>';
    } else {
        $result='<div class="alert alert-danger">Sorry there was an error sending your message. Please try again later</div>';
    }
}
    }
?>
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="description" content="My very first website.">
  <meta name="author" content="Reprevise">
  <meta name="keywords" content="My development portfolio.">
  <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
  <title>Reprevise | Home</title>
  <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">
  <link rel="stylesheet" type="text/css" href="assets/css/layout.css">
  <link rel="stylesheet" type="text/css" href="assets/css/theme.css">
  <link rel="shortcut icon" href="assets/images/favicon.ico" type="image/x-icon">
  <link rel="icon" href="assets/images/favicon.ico" type="image/x-icon">
</head>
<body>
  <nav class="nav" id="homelink">
    <div class="container">
      <div class="logo">
        <img class="sitelogo" src="assets/images/logo.jpg" alt="logo">
      </div>
      <ul class="menu">
        <li><a href="#homelink">Home</a></li>
        <li><a href="#aboutlink">About</a></li>
        <li><a href="#contact">Contact</a></li>
      </ul>
    </div>
  </nav>
  <header>
    <div class="title-wrapper">
      <h1 class="header-title">reprevise's dev studio</h1>
    </div>
  </header>
  <div class="aboutsection" id="aboutlink">
    <div class="headingtitle-wrapper">
      <h1>About Reprevise</h1>
    </div>
    <div class="about-paragraph">
      <p style="text-align: left;">Benjamin, otherwise known as Benjamin has been a developer of all different types of programming languages for about 3 years now. He has knowledge of Lua, Java, HTML, CSS, JS, C#, and Python. Ben loves to make Minecraft plugins for all sorts of
        clients for free! Below is a contact form in which you can hit him up if you have a plugin request.</p>
    </div>
  </div>
  <div class="conform-container">
    <div id="contact">
      <div class="conform-heading-wrapper">
        <h1>Contact Form</h1>
        <h4>Send me plugin requests here.</h4>
      </div>
      <form class="form-horizontal" role="form" method="post" action="form-handler.php">
        <div class="form-group">
          <label for="name" class="col-sm-2 control-label">Name</label>
          <div class="col-sm-10">
            <input type="text" class="form-control" id="name" name="name" placeholder="First & Last Name" value="<?php echo htmlspecialchars($_POST['name']); ?>">
            <?php echo "<p class='text-danger'>$errName</p>";?>
          </div>
        </div>
        <div class="form-group">
          <label for="email" class="col-sm-2 control-label">Email</label>
          <div class="col-sm-10">
            <input type="email" class="form-control" id="email" name="email" placeholder="example@domain.com" value="<?php echo htmlspecialchars($_POST['email']); ?>">
            <?php echo "<p class='text-danger'>$errEmail</p>";?>
          </div>
        </div>
        <div class="form-group">
          <label for="subject" class="col-sm-2 control-label">Subject</label>
          <div class="col-sm-10">
            <input type="text" class="form-control" id="subject" name="subject" placeholder="Really Important Plugin" value="<?php echo htmlspecialchars($_POST['subject']); ?>">
            <?php echo "<p class='text-danger'>$errSubject</p>";?>
          </div>
        </div>
        <div class="form-group">
          <label for="message" class="col-sm-2 control-label">Message</label>
          <div class="col-sm-10">
            <textarea class="form-control" rows="4" name="message"><?php echo htmlspecialchars($_POST['message']);?></textarea>
            <?php echo "<p class='text-danger'>$errMessage</p>";?>
          </div>
        </div>
        <div class="form-group">
          <div class="col-sm-10 col-sm-offset-2">
            <input id="submit" name="submit" type="submit" value="Send" class="btn btn-primary">
          </div>
        </div>
        <div class="form-group">
          <div class="col-sm-10 col-sm-offset-2">
            <?php echo $result; ?>
          </div>
        </div>
      </form>
    </div>
  </div>
  <script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js" integrity="sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q" crossorigin="anonymous"></script>
  <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js" integrity="sha384-JZR6Spejh4U02d8jOt6vLEHfe/JQGiRRSQQxSfFWpi1MquVdAyjUar5+76PVCmYl" crossorigin="anonymous"></script>
</body>
</html>
 
     
    