单击 PHP 中的按钮后如何重定向到 URL

Question

This is my php code which I called registerprocess.php This code occurs after I click a submit button on another code called userregistration.php

I wanted registerprocess.php to redirect the page to the userregistration.php if the user registering is using an email that already exists in the database.

And if the user registers with an email that is not in the database, I would want it to redirect to mainpage.php

I tried using window.location.href to redirect my page but it did not work. Is there another way I could redirect my page?

<?php
    session_start();
    $dbhost = "localhost";
    $dbname = "registration";
    $dbuser = "root";
    $dbpass = "password";

    $conn = mysqli_connect($dbhost, $dbuser, $dbpass, $dbname);

    if ($conn->connect_error) {
        die("Connect failed: " . $conn->connect_error);
    }
    $UserId = mysqli_real_escape_string($conn, $_POST['UserId']);
    $email = mysqli_real_escape_string($conn, $_POST['email']);
    $password = mysqli_real_escape_string($conn . $_POST['password_1']);
    $password = mysqli_real_escape_string($conn . $_POST['password_2']);
    $duplicate = mysqli_query($conn, "SELECT * FROM users WHERE email='$email' ");
    if (mysqli_num_rows($duplicate) > 0) {
        $url = $_SESSION['url'];
        echo("<script language='javascript'>
            window.alert('Email already been taken')
            window.location.href='https://easymoney.com/userregistration.php' ;
        </script>");
    } else {
        $sql = "INSERT INTO users (email, password, UserId) VALUES ('$email', '$password','$UserId' )";
        $result = mysqli_query($conn, $sql);

        if ($result) {
            $url = $_SESSION['url'];
            echo("<script language='javascript'>
                window.alert('successful')
                window.location.href='https://easymoney.com/mainpage.php';
            </script>");
        } else {
            $url = $_SESSION['url'];
            echo("<script language='javascript'>
                window.alert('error')
                window.location.href='$url';
            </script>");
        }
    }
?>

Answer 1

已经有预定义的头函数可以在 php 中重定向。

header("Location: $url");