與isset（）函數功能

Question

PHP WordPress的問題，所有這些代碼寫在同一頁

<form method="post" action = "http://mypage.lhosting.info/login/" > 
    <p> Username: <input type="text" name = "username" /> </p><br> 
    <p> Password: <input type="text" name = "password" /></p> <br> 
    <input type="submit" name="submit" value="Register" /> 
</form> 

if(isset($_POST['submit']) && !empty($_POST['submit'])) 
{ 
    $username = mysqli_real_escape_string($conn, $_POST['username']); 
    $password = mysqli_real_escape_string($conn, $_POST['password']); 
    $sql = "INSERT INTO Duomenys (Username, Password) VALUES ('$username','$password')"; 
} 

的if(isset($_POST['submit']) && !empty($_POST['submit']))沒有觸發，它將發送帳戶的詳細資料到我的數據庫，每次我刷新頁面。我究竟做錯了什麼？

注：仍在學習PHP和WordPress

Answer 1

$_POST['submit']永遠設置和不是空它的價值已經被設置爲註冊。

您需要檢查username和password不應爲空。因此寫

if(!empty($_POST['username']) && !empty($_POST['password'])){ 
    // querycode here 
}