Create interactive web forms using PHP functions

PHP provides functions for creating and processing interactive web forms, including: creating form elements (using HTML to define fields); using $_POST or $_GET to access form data; using filter_var() to validate input; using error messages Handle validation errors.

Using PHP functions to create interactive web forms

A wide range of functions are provided in PHP to help create and process interactive web forms form. This article explains how to use these functions to build a fully functional form.

1. Create form elements

We use HTML to define form elements as follows:

<form action="process.php" method="post">
  <label for="name">姓名：</label>
  <input type="text" id="name" name="name" required>

  <label for="email">邮箱：</label>
  <input type="email" id="email" name="email" required>

  <input type="submit" value="提交">
</form>

2. Use PHP functions Processing form data

After the user submits the form, you can use the $_POST or $_GET function to access the form data.

For the above form, we can use the following PHP code to process the data:

<?php
if ($_SERVER["REQUEST_METHOD"] == "POST") {
  $name = $_POST['name'];
  $email = $_POST['email'];

  // 在这里处理表单数据
}
?>

3. Validate form input

In order to ensure that the form input is valid, you can Use PHP's verification function, such as filter_var():

<?php
if (filter_var($email, FILTER_VALIDATE_EMAIL)) {
  // 有效的电子邮件地址
} else {
  // 无效的电子邮件地址
}
?>

4. Handle errors

If you encounter a verification error, you can use the following code Display error message:

<?php
if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
  echo "<p>无效的电子邮件地址</p>";
}
?>

Practical case

The following is an example of using the above function to create an interactive user registration form:

<!-- form.php -->
<form action="process.php" method="post">
  <label for="username">用户名：</label>
  <input type="text" id="username" name="username" required>

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

  <input type="submit" value="注册">
</form>

<!-- process.php -->
<?php
if ($_SERVER["REQUEST_METHOD"] == "POST") {
  // 获取表单数据
  $username = $_POST['username'];
  $password = $_POST['password'];

  // 验证表单输入
  if (!preg_match('/^[a-zA-Z0-9]+$/', $username)) {
    echo "<p>无效的用户名</p>";
  } else if (!preg_match('/^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)[a-zA-Z\d]{8,}$/', $password)) {
    echo "<p>无效的密码</p>";
  } else {
    // 密码散列和插入数据库
    $hashedPassword = password_hash($password, PASSWORD_DEFAULT);
    $query = "INSERT INTO users (username, password) VALUES (?, ?)";
    $stmt = $conn->prepare($query);
    $stmt->bind_param('ss', $username, $hashedPassword);
    $stmt->execute();

    echo "<p>注册成功！</p>";
  }
}
?>

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