如果任何一个字段为空或未正确填写，则不应提交表单？

Question

如果任何一个字段为空或未正确填写，则不应提交

表单？ 当在cnic字段中输入时应该是14个数字，但是输出应该像12345-67891023-4这个deshes应该在输出中自动添加如何才能超过这个？

<form method="get" action="example1.php">
    Name : <input type="text" name="fname" value="" >
    <br>
    Last Name : <input type="text" name="lname" value="">
    <br>
    CNIC # <input type="text" name="cnic" value="">
    <br>
    Email : <input type="text" name="email" value="">
    <br>
    Contact # <input type="text" name="contact" value="">
    <br>
    <input type="submit" name="submit" value="submit">
    </form>

    <?php 



    if(isset($_GET['submit'])){
        $name =$_GET['fname'];
        $lname = $_GET['lname'];
        $cnic = $_GET['cnic'];
        $email = $_GET['email'];
        $contact = $_GET['contact'];



        $patternn = "/[A-Za-z]/";
        $a = preg_match($patternn,$name);
        if ($a){
            echo "<br>First Name : ".$name;
            }
            else {
            echo    "<br>please enter name";
                }


                $patterln = "/[a-z]/";
        $b = preg_match($patterln,$lname);
        if ($b){
            echo "<br>Last Name : ".$lname;
            }
            else {
            echo    "<br> please enter last name";
                }


        $patternnic = "/[0-9]{14}/";
        $c = preg_match($patternnic,$cnic);
        if ($c){

            echo "<br> NIC: ".$cnic;
            }
            else {
            echo    "<br> please enter nic";
                }



        $patterne = "/[a-z]/";
        $d= preg_match($patterne,$email);
        if ($d){
            echo "<br> Email : ".$email;
            }
            else {
            echo    "<br>please enter email";
                }

                $patternc = "/[0-9]/";
        $e = preg_match($patternc,$contact);
        if ($e){
            echo "<br> Contact : ".$contact;
            }
            else {
            echo    "<br>please enter name";
                }



}


    ?>

如果任何一个字段为空或未正确填充，则不应提交

表单？