PHP代碼在提交表單之前正在執行

Question

<?php 
function log_page(){ 
    print_r($_POST); 
    //connection variables 
$host = 'localhost'; 
$user = 'root'; 
$password = ''; 
$db = 'firstwebsite'; 

//create mysql connection 
$mysqli = mysqli_connect($host,$user,$password); 
if(!$mysqli){ 
    echo " connection"; 
} 
else{ 
    echo "no connection"; 
} 
$select = mysqli_select_db($mysqli, $db); 

    $_SESSION['message']=''; 

    if (isset($_POST['register'])) { 
    if ($_POST['password'] == $_POST['confirmpassword']) 
    { 
     $$username = $mysqli->real_escape_string($_POST['username']); 
     $email = $mysqli->real_escape_string($_POST['email']); 
     $password = md5($_POST['password']); 

     echo $username . " " . $email . " " . $password; 
    } 
    } 
?> 
<link rel="stylesheet" href="log_style.css" type="text/css"> 
<div class="body-content"> 
    <div class="module"> 
    <h1>Create an account</h1> 
    <form class="form" action="log_page.php" method="post" autocomplete="off"> 
     <input type="text" placeholder="User Name" name="username" required /> 
     <input type="email" placeholder="Email" name="email" required /> 
     <input type="password" placeholder="Password" name="password" autocomplete="new-password" required /> 
     <input type="password" placeholder="Confirm Password" name="confirmpassword" autocomplete="new-password" required /> 
     <input type="submit" value="Register" name="register" class="btn btn-block btn-primary" /> 
     <input type="submit" value="Already registered? Sign in" name="register2" class="btn btn-block btn-primary" /> 
    </form> 
    </div> 
</div> 
<?php 
} 
?> 

當我要求回顯用戶名和電子郵件和密碼時，我的代碼不會打印任何內容。它沒有輸入$ _POST ['register'] if語句。我認爲PHP代碼在執行表單值之前執行

Answer 1

請勿在表單中使用相同的名稱。如果你沒有上傳表單中的文件，你也不需要enctype="multipart/form-data"。

<form class="form" action="log_page.php" method="post" autocomplete="off"> 
       <input type="text" placeholder="User Name" name="username" required /> 
       <input type="email" placeholder="Email" name="email" required /> 
       <input type="password" placeholder="Password" name="password" autocomplete="new-password" required /> 
    <input type="password" placeholder="Confirm Password" name="confirmpassword" autocomplete="new-password" required /> 
      <input type="submit" value="Register" name="register" class="btn btn-block btn-primary" /> 
      <input type="submit" value="Already registered? Sign in" name="register2" class="btn btn-block btn-primary" /> 
</form> 

請注意，這應該在你的log_page.php;

if ($_POST['register']) { 
    if ($_POST['password'] == $_POST['confirmpassword']) 
    { 
     $username = $mysqli->real_escape_string($_POST['username']); 
     $email = $mysqli->real_escape_string($_POST['email']); 
     $password = md5($_POST['password']); 

echo $username . " " . $email . " " . $password; //test purpose 
    } 
}