Unveiling the Essence of PHP: A Deep Dive into the English Website Source Code，php网站源码完整

PHP, a server-side scripting language, has been the backbone of countless websites across the globe. Its simplicity, flexibility, and robustness have made it a preferred choice for web developers. In this article, we will explore the English website source code written in PHP, unraveling its mysteries and shedding light on the intricacies of the language.

To begin with, let's take a look at the basic structure of a PHP script. A PHP script starts with the opening tag<?php and ends with the closing tag?>. Within these tags, we can write PHP code, HTML, and CSS. However, it is essential to keep PHP code and HTML separate for better readability and maintainability.

Consider the following example of a simple PHP script that displays a welcome message:

<?php
echo "Welcome to our website!";
?>

In this script, theecho statement is used to output the message "Welcome to our website!" to the browser. The<?php and?> tags define the boundaries of the PHP code, while theecho statement is a built-in function that prints the specified string.

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Now, let's delve deeper into the world of PHP by examining some essential concepts and functions.

1、Variables: Variables are used to store data in PHP. They are declared using the$ symbol followed by the variable name. For example:

<?php
$age = 25;
$name = "John Doe";
?>

In this example, the variable$age is assigned the value25, and the variable$name is assigned the value "John Doe". We can then use these variables in our PHP code to display personalized information.

2、Control Structures: PHP provides various control structures, such asif,else,switch, and loops, to control the flow of execution in a script. For instance, the following code snippet demonstrates the use of anif statement:

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<?php
$age = 18;
if ($age >= 18) {
    echo "You are an adult.";
} else {
    echo "You are not an adult.";
}
?>

In this example, theif statement checks whether the value of$age is greater than or equal to 18. If the condition is true, the message "You are an adult." is displayed; otherwise, the message "You are not an adult." is shown.

3、Functions: Functions are reusable blocks of code that perform specific tasks. PHP provides a wide range of built-in functions, and developers can also create their custom functions. Here's an example of a custom function that calculates the square of a number:

<?php
function square($number) {
    return $number * $number;
}
echo "The square of 5 is: " . square(5);
?>

In this code, thesquare function takes a number as input and returns its square. Theecho statement then displays the result of calling thesquare function with the argument5.

4、Database Interaction: PHP is often used in conjunction with databases, such as MySQL, to retrieve and store data. The following example demonstrates how to connect to a MySQL database and fetch data using PHP:

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<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";
// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}
$sql = "SELECT id, firstname, lastname FROM MyGuests";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
    // output data of each row
    while($row = $result->fetch_assoc()) {
        echo "id: " . $row["id"]. " - Name: " . $row["firstname"]. " " . $row["lastname"]. "<br>";
    }
} else {
    echo "0 results";
}
$conn->close();
?>

In this code, we establish a connection to a MySQL database using themysqli extension. We then execute a SQL query to fetch data from theMyGuests table. If there are any rows returned, we iterate through them and display theid,firstname, andlastname columns.

In conclusion, PHP is a powerful and versatile language that enables developers to create dynamic and interactive websites. By understanding the basics of PHP, such as variables, control structures, functions, and database interaction, developers can build robust and scalable web applications. This article has provided a glimpse into the world of PHP by examining an English website source code, highlighting the essential concepts and functions that make PHP a valuable tool in the web development toolkit.

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