PHP : Complete Form Example

Here's a complete example of an HTML form with PHP validation for name, email, and URL fields:

HTML Form (index.html):

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Form Example</title>
</head>
<body>
    <h2>Form Example</h2>
    <form action="process_form.php" method="post">
        <label for="name">Name:</label>
        <input type="text" id="name" name="name" value="<?php echo isset($_POST['name']) ? htmlspecialchars($_POST['name']) : ''; ?>" required><br>

        <label for="email">Email:</label>
        <input type="email" id="email" name="email" value="<?php echo isset($_POST['email']) ? htmlspecialchars($_POST['email']) : ''; ?>" required><br>

        <label for="url">URL:</label>
        <input type="url" id="url" name="url" value="<?php echo isset($_POST['url']) ? htmlspecialchars($_POST['url']) : ''; ?>" required><br>

        <input type="submit" value="Submit">
    </form>
</body>
</html>