How to use PHP to determine whether two password inputs are consistent-PHP Problem-php.cn

How to use PHP to determine whether two password inputs are consistent

PHPz

Release： 2023-04-10 10:17:47

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PHP form validation is a very important link in web development. It can effectively reduce the possibility of users entering illegal data. When users register or change passwords, it is a common requirement to prevent users from entering inconsistent passwords. This article will introduce how to use PHP code to determine whether two password inputs are consistent.

(1) Form design

First, we need to create a form in the HTML page for users to enter passwords and confirm passwords. The HTML code is as follows:

<form action="register.php" method="post">
  <label for="password">密码：</label>
  <input type="password" name="password" id="password" required>

  <label for="confirm_password">确认密码：</label>
  <input type="password" name="confirm_password" id="confirm_password" required>

  <button type="submit">注册</button>
</form>

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The required attribute of HTML5 is used here to ensure that the user must enter a password and confirm the password. In addition, the name attributes of the two password input boxes are password and confirm_password respectively, which are used to receive the values entered by the user.

(2) PHP code implementation

Next, we need to write PHP code to compare whether the two password inputs are consistent. First, in the register.php file, we can use the isset() function to determine whether the user has submitted the form. If the user submits the form, we can obtain the password and confirmation password entered by the user through the $_POST array, and then compare them.

if (isset($_POST['password']) && isset($_POST['confirm_password'])) {
  $password = $_POST['password'];
  $confirm_password = $_POST['confirm_password'];

  if ($password != $confirm_password) {
    echo "两次密码不一致";
  } else {
    // 表单验证通过，执行注册逻辑
  }
}

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The above code first uses the isset() function to determine $_POST['password'] and $_POST['confirm_password'] exists to ensure the user has submitted the form. Then, obtain the password and confirmation password entered by the user through the $_POST array, and use the != operator to compare whether they are consistent. If they are inconsistent, the prompt message "Two passwords are inconsistent" will be output, otherwise the registration logic will be executed.

If we want to increase the friendliness of the prompt information, we can use the <span> tag to wrap the prompt information and set the CSS style.

if ($password != $confirm_password) {
  echo '<span style="color: red;">两次密码不一致</span>';
}

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The style attribute is used here to set the CSS style so that the prompt information appears in red font.

(3) Complete sample code

The following is a complete sample code, which compares the two passwords entered by the user and outputs the corresponding prompt information.

<!DOCTYPE html>
<html>
<head>
    <title>PHP两次密码不一致代码示例</title>
</head>
<body>
    <h1>注册</h1>

    <form action="register.php" method="post">
        <label for="password">密码：</label>
        <input type="password" name="password" id="password" required>

        <label for="confirm_password">确认密码：</label>
        <input type="password" name="confirm_password" id="confirm_password" required>

        <button type="submit">注册</button>
    </form>

    <?php
    if (isset($_POST['password']) && isset($_POST['confirm_password'])) {
        $password = $_POST['password'];
        $confirm_password = $_POST['confirm_password'];

        if ($password != $confirm_password) {
            echo '<span style="color: red;">两次密码不一致</span>';
        } else {
            // 表单验证通过，执行注册逻辑
            // ...
        }
    }
    ?>
</body>
</html>

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As the amount of data input and data types in web applications increases, form validation becomes more and more important. Through the above demonstration, developers can understand how to use PHP code to implement the function of judging whether two password inputs are consistent. Of course, this is just the basis of form validation. There are many other validation methods and techniques worth learning and exploring in depth.

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