signupback.php

<?php
session_start();
$username = filter_input(INPUT_POST, 'username');
$password = filter_input(INPUT_POST, 'password');
$c_id = filter_input(INPUT_POST, 'c_id');
$c_ph = filter_input(INPUT_POST, 'c_ph');
$email = filter_input(INPUT_POST, 'email');
$address = filter_input(INPUT_POST, 'address');
$experience = filter_input(INPUT_POST, 'experience');
$r_password = filter_input(INPUT_POST, 'rpassword');
if (!empty($username)) {
    if (!empty($address)) {
        if (!empty($c_ph)) {
            if (!empty($email)) {
                if (!empty($experience)) {
                    if (!empty($password)) {
                        if ($password == $r_password) {
                            require "dbh.php";

                            $hashedpwd = password_hash($password, PASSWORD_DEFAULT);
                            $sql = "Insert into customer(C_Name,Address,C_Ph_Number,Email,Exp,C_Pass)
                                   values('$username','$address','$c_ph','$email','$experience','$hashedpwd')";

                            if ($conn->query($sql)) {
                                echo "Sign Up successfull.";
                                header("Location: timeoutup2in.html");
                            } else {
                                echo "Error" . $sql . "<br>" . $conn->error;
                            }
                            $conn->close();
                        } else {
                            echo "<script>alert('Password deos not match!');window.location='signup.html'</script>";
                        }
                    } else {
                        echo "Password should not be empty";
                    }
                } else {
                    echo "Experience should not be empty";
                }
            } else {
                echo "Email should not be empty";
            }
        } else {
            echo "Phone Number should not be empty";
        }
    } else {
        echo "Address should not be empty";
    }
} else {
    echo "Username should not be empty";
}