Every time I press submit. It goes straight to the (action) page without checking to see if any value is filled in.How do I stop it from changing pages without first checking to see if any information is filed in the name email and comment?

```
<?php
        if( empty($name) && isset($_POST["submit"])){
            global $connect;
            $name = $_POST['name'];
            $email = $_POST['email'];
            $comment = $_POST["comment"];

            $sql = "INSERT INTO entries (fullName,email,comment)
            VALUES ('$name', '$email', '$comment')";
            $result = mysqli_query($connect, $sql);
            if(!$result){
                die("try again" .mysqli_error());
            }
        }
    ?>

    <section>
   <div class="container text-center ">
      <h1>Guess Book</h1>
       <div class="row"></div>
       <form class="text-center" action="thankYou.php" method="post" id="signUp" >
        <label class="mb-2 mt-2" style="padding-right:1vh"  for="name">Please Enter Your Full Name Here:</label><input  type="text" name="name" placeholder="Enter Full Name"  minlength="3" ><br>
        <label class="mb-2 mt-2" style="padding-right:4.1vh" for="email">Please Enter Your Email Here:</label><input type="email" name="email" placeholder="Enter Email"  minlength="4" ><br>
            <div class="form-group ">
              <label for="comment">Comment:</label>
              <textarea name="comment" class="form-control mb-3" rows="8" minlength="4" id="comment"></textarea>
           </div>
           <input class="bottom-pad" type="submit" name="submit">
       </form>
   </div>
  </section> 

```