| Introduction to Web Development |
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| Basic PHP Syntax |
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| PHP Basics |
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| Variables and Data Types |
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| Functions in PHP |
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| User-defined Functions |
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| Built-in Functions |
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| Variable Scope |
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| Include and Require |
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| Working with Forms |
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| Forms in HTML |
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| Form Handling in PHP |
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| Working with Files |
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| File Handling |
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| File System Functions |
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| Working with Databases |
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| Introduction to Databases |
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| Advanced PHP Techniques |
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| Object-Oriented Programming (OOP) |
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| Error and Exception Handling |
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Basic Syntax
PHP code can be embedded in HTML using the PHP tags: ‘<?php ... ?>‘. Any code written within these tags will be executed on the server before the HTML is sent to the client.
Example:
<!DOCTYPE html>
<html>
<head>
<title>My PHP Page</title>
</head>
<body>
<h1>Welcome to my website</h1>
<?php
echo "<p>This is a paragraph generated by PHP!</p>";
?>
</body>
</html>
In this example, the PHP code within <?php ... ?> tags outputs a paragraph element.
Using Short Tags
PHP also supports short tags <? ... ?> and <?= ... ?> (the latter is used for outputting values directly).
Example:
<!DOCTYPE html>
<html>
<head>
<title>Short Tags Example</title>
</head>
<body>
<h1>Using Short Tags</h1>
<? echo "<p>This is a paragraph generated by PHP using short tags!</p>"; ?>
<?= "<p>This is another way to echo content using <?= ... ?>.</p>" ?>
</body>
</html>
Mixing HTML and PHP
You can switch between HTML and PHP as needed. This allows you to seamlessly integrate server-side logic with your HTML.
Example:
<!DOCTYPE html>
<html>
<head>
<title>Dynamic Content Example</title>
</head>
<body>
<h1>Dynamic Content</h1>
<?php
$hour = date("H");
if ($hour < 12) {
echo "<p>Good morning!</p>";
} elseif ($hour < 18) {
echo "<p>Good afternoon!</p>";
} else {
echo "<p>Good evening!</p>";
}
?>
</body>
</html>
In this example, PHP is used to generate a different greeting based on the time of day.
Handling Forms with PHP
One of the most common uses of PHP is handling form submissions. Here’s a simple example:
Example:
<!DOCTYPE html>
<html>
<head>
<title>Form Handling with PHP</title>
</head>
<body>
<h1>Contact Us</h1>
<form method="post" action="">
Name: <input type="text" name="name"><br>
Email: <input type="email" name="email"><br>
<input type="submit">
</form>
<?php
if ($_SERVER["REQUEST_METHOD"] == "POST") {
$name = htmlspecialchars($_POST['name']);
$email = htmlspecialchars($_POST['email']);
echo "<p>Thank you, $name. We will contact you at $email.</p>";
}
?>
</body>
</html>
In this example, the form data is processed by PHP, which then outputs a message using the submitted data.
Including Files
PHP allows you to include other PHP files within your code using ‘include or require‘. This is useful for separating concerns and reusing code.
Example:
header.php
<!DOCTYPE html>
<html>
<head>
<title>My Website</title>
</head>
<body>
<header>
<h1>My Website Header</h1>
</header>
footer.php
<footer>
<p>Footer content here</p>
</footer>
</body>
</html>
index.php
<?php include 'header.php'; ?>
<main>
<h2>Welcome to my website</h2>
<p>This is the main content.</p>
</main>
<?php include 'footer.php'; ?>
In this example, ‘header.php‘ and ‘footer.php‘ are included in ‘index.php‘, which helps maintain a consistent layout.
Using PHP for Dynamic Content
PHP can be used to interact with databases, manage sessions, and handle cookies, allowing for the creation of fully dynamic websites.
Database Example (MySQL):
<!DOCTYPE html>
<html>
<head>
<title>Database Example</title>
</head>
<body>
<h1>User List</h1>
<?php
$conn = new mysqli("localhost", "username", "password", "database");
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
$sql = "SELECT id, name, email FROM users";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
echo "<ul>";
while($row = $result->fetch_assoc()) {
echo "<li>" . $row["name"] . " (" . $row["email"] . ")</li>";
}
echo "</ul>";
} else {
echo "<p>No users found.</p>";
}
$conn->close();
?>
</body>
</html>
In this example, PHP connects to a MySQL database, retrieves user data, and dynamically generates an HTML list of users.
