Ajax 验证在 html 元素内重复 html 页面

Question

我使用 Ajax 进行的 PHP 用户名验证在 html div（这是为了显示 ajax 错误）元素中复制了我的 html 页面。我尝试了一些解决方案并用谷歌搜索，但找不到其他解决方案。也许问题出在 $_POST 但我也在 php 中将它们分开（所有输入验证）。这是PHP代码<?php if(isset($_POST['username'])){    //username validation    $username = $_POST['username'];    if (! $user->isValidUsername($username)){        $infoun[] = 'Your username has at least 6 alphanumeric characters';    } else {        $stmt = $db->prepare('SELECT username FROM members WHERE username = :username');        $stmt->execute(array(':username' => $username));        $row = $stmt->fetch(PDO::FETCH_ASSOC);        if (! empty($row['username'])){            $errorun[] = 'This username is already in use';        }    }}if(isset($_POST['fullname'])){    //fullname validation    $fullname = $_POST['fullname'];    if (! $user->isValidFullname($fullname)){        $infofn[] = 'Your name must be alphabetical characters';    }   }if(isset($_POST['password'])){    if (strlen($_POST['password']) < 6){        $warningpw[] = 'Your password must be at least 6 characters long';    }   }if(isset($_POST['email'])){    //email validation    $email = htmlspecialchars_decode($_POST['email'], ENT_QUOTES);    if (! filter_var($email, FILTER_VALIDATE_EMAIL)){        $warningm[] = 'Please enter a valid email address';    } else {        $stmt = $db->prepare('SELECT email FROM members WHERE email = :email');        $stmt->execute(array(':email' => $email));        $row = $stmt->fetch(PDO::FETCH_ASSOC);        if (! empty($row['email'])){            $errorm[] = 'This email is already in use';        }    }}?>这是屏幕截图：

Answer 1

PHP 文件中唯一的代码应该在<?php ?>标签内。您需要将 PHP 代码分离到另一个文件中。