Why isn’t the alert box appearing?

This is my HTML and JS code:

<!DOCTYPE html>
<html>
    <head>
        <script>
            function validateForm() {
                let x = document.forms["myForm"]["fname"].value;
                 if (x == "") {
                    alert("Name must be filled out");
                    return false;
                }
            }

            function validateForm() {
                let x = document.forms[myForm][lname].value;
                if (x == "") {
                    alert("Last name should be filled out");
                    return false;
                }
                else
                    alert("Thank you for your response");
            }
        </script>
    </head>

    <body>
        <h1>Student Information Form</h1>

        <br>
        <br>

        <form name="myForm" onsubmit="return validateForm()" method="post">
            <label for="fname">First name:</label><br>
            <input type="text" id="fname" name="fname"><br>
            <label for="lname">Last name:</label><br>
            <input type="text" id="lname" name="fname"><br> <br>
            <label for="email">Email:</label>
            <input type="text" id="email" name="email">

            <input type="reset">
            <input type="submit" value="Submit">
        </form>
    </body>
</html>

And upon clicking the submit button I’m calling the alert to appear but it’s not appearing. When I have data in the input tags, when I click submit the data just dissapears. Why is this happening???