SignUp.js

$(document).ready(function () {
    $("form").submit(function (event) {
        $(".form-group").removeClass("has-error");
        $(".help-block").remove();

        var formData = {
            Fname: $("#Fname").val(),
            Lname: $("#Lname").val(),
            email: $("#email").val(),
            password: $("#password").val(),
            password2: $("#password2").val(),
            phone: $("#phone").val(),
            street: $("#street").val(),
            city: $("#city").val(),
            country: $("#country").val(),
        };

        // console.log(formData);

        if (!isValidData(formData))
            return;
        else
            $.ajax({
                type: "POST",
                url: "SignUp.php",
                data: formData,
                dataType: "json",
                encode: true,
            })
                .done(function (data) {
                    // console.log(data);
                    if (!data.success) { // Error
                        // console.log(data);
                    } else { // Success
                        $("form").html('<script></script>' + '<div class="alert alert-success">' + data.message + "</div>");
                        window.location.href = 'homepage.html';
                    }
                    alert(data.message);
                })
                .fail(function (data) {
                    alert("AJAX FAIL !");
                });

        event.preventDefault();

    });

});

function isValidData(formData) {
    let valid = true;

    if (formData["Fname"] === '' || formData["Lname"] === '') {
        alert("Please Enter your Full Name");
        valid = false;
    }

    if (formData["email"] === '') {
        alert("Please Enter your Email");
        valid = false;
    }

    if (formData["password"] === '') {
        alert("Please Enter your Password");
        valid = false;
    }

    if (formData["password2"] === '' || formData["password2"].localeCompare(formData["password"])) {
        alert("Please Confirm your Password");
        valid = false;
    }

    if (formData["phone"] === '' || isNaN(formData["phone"])) {
        alert("Please Enter your Correct Phone Number");
        valid = false;
    }

    if (formData["street"] === '' || formData["city"] === '' || formData["country"] === '') {
        alert("Please Enter your Full Address");
        valid = false;
    }
    return valid
}