Jquery return php code after ajax success

Question

<script type="text/javascript">
    $(document).ready(function(){
        $("#submitform").click(function(e){
            e.preventDefault();
            fname = $(".fname").val();
            subject = $(".subject").val();
            email = $(".email").val();
            phone = $(".phone").val();
            comment = $(".comment").val();
            $.ajax({
                type:"POST",
                data:{"fname":fname, "subject":subject, "email":email, "phone":phone,"comment":comment},
                url:"http://example/contact/send.php",
                contentType: "application/json; charset=utf-8",
                success:function(res){
                    console.log(res);
                }
            });
        });
    });
</script>

send.php

<?php
    $fname = $_POST['fname'];
    $subject = $_POST['subject'];
    $email = $_POST['email'];
    $phone = $_POST['phone'];
    $comment = $_POST['comment'];
    echo $fname;
?>

In the above code I am trying to get $fname in my console.log but what happen here when I click on submit button then it show whole PHP code in my console. I don't know why this happening? Please help me.

Thank You