Introduction to PHP for WordPress Development
PHP (Hypertext Preprocessor) is a widely used open-source scripting language that is especially suited for web development and can be embedded into HTML. It is a server-side language, which means that it runs on the server and generates dynamic content that is sent to the client’s web browser.
Never writing a single line of code, many WordPress website owners operate profitable blogs, e-commerce sites, and companies. Understanding the basics will help you stand out from the competition even if you aren’t a programming expert to run a website.
Thankfully, you don’t have to devote years to mastering the complexities of programming. Learn the basic syntax and get comfortable with how WordPress utilizes its core programming languages to open up possibilities.
At ARZ Host, we’ll examine PHP’s function in the most widely used Content Management System (CMS) worldwide in this article. Next, we’ll walk you through building a few basic PHP methods to tweak the WordPress platform, themes, and plugins.
Now let’s get going!
What is PHP? A Powerful Programming Language
Almost 80% of websites that use programming languages are made with PHP, an open-source programming language. Since PHP is a server-side language, much of its processing takes place on your server.
The PHP module that is installed on your web server processes this code whenever a visitor requests a page that contains PHP. After that, the pre-processor creates the HTML output and delivers it to the browser of the visitor.
The PHP code found in your theme, core files, and any installed plugins will be executed by the server whenever someone visits your WordPress website. Your server will send the HTML code to the web browser after processing all of that PHP. This implies that the PHP code that drives your WordPress website will never be seen by the visitor; on the contrary, they will only ever see the processed HTML.
Similar to other programming languages, PHP comes in a variety of versions. As of this writing, PHP 7.3 is the last version that is still supported, and 8.0.8 is the most recent release.
Thus, security fixes and updates for previous iterations of PHP are no longer released by the developers. Therefore, we advise against using any version of PHP earlier than 7.3. See how to check your PHP Version.
Here are some key points about PHP:
- Server-Side Scripting: PHP is executed on the server, generating HTML which is then sent to the client. This allows for dynamic content creation.
- Embedding in HTML: PHP can be embedded directly within HTML, making it easy to add functionality to web pages without needing to call external files.
- Database Interaction: PHP supports numerous databases (e.g., MySQL, PostgreSQL), making it ideal for creating data-driven websites.
- Syntax: PHP’s syntax is similar to C and Perl, making it relatively easy to learn for those familiar with these languages.
- Wide Support: PHP is supported by most web hosting providers, making it accessible for developers of all levels.
- Frameworks and CMS: There are numerous frameworks (e.g., Laravel, Symfony) and content management systems (e.g., WordPress, Drupal) built with PHP, offering robust tools for development.
- Community and Resources: PHP has a large and active community, providing extensive documentation, tutorials, and support.
PHP is versatile and can be used to create a wide range of web applications, from simple websites to complex enterprise-level applications.
Why PHP Is Important for Website Owners?
Maintaining a profitable WordPress website doesn’t require you to be an expert in PHP. Choosing WordPress as your content management system (CMS) has the benefit of having most of the PHP code already prepared for you. The majority of WordPress users, in fact, never learn the basics of this widely used programming language.
Yet, knowing PHP has certain advantages. WordPress is a strong and versatile CMS right out of the box, but there can be instances in which the built-in features are insufficient.
Basic PHP knowledge will enable you to develop more complex and unique modifications if you wish to change WordPress’ default behaviors. You may leverage the various hooks, classes, and functions that WordPress offers to expand this platform in new and exciting ways.
PHP is also necessary if you want to create your own WordPress theme or plugin. You may also change the underlying code of many themes and plugins because they are open sources.
Modifying these pre-existing PHP files could still be helpful even if you have no plans to create a theme or plugin from scratch. You’ll be able to customize that theme or plugin to make it the ideal match for your WordPress website by mastering the fundamental syntax.
Here are several reasons why PHP is important for website owners:
- Open Source and Free: PHP is open-source and free to use, making it a cost-effective solution for website owners. There are no licensing fees associated with using PHP, and a large community of developers contributes to its development and improvement.
- Easy to Learn and Use: PHP is relatively easy to learn, especially for those who are already familiar with programming languages like HTML and JavaScript. Its syntax is straightforward, which helps new developers get up to speed quickly.
- Versatile and Flexible: PHP can be used to develop a wide range of web applications, from simple websites to complex e-commerce platforms. It supports various databases, including MySQL, PostgreSQL, and SQLite, providing flexibility in choosing the right database for your project.
- Large Community and Support: PHP has a vast and active community of developers who contribute to forums, write tutorials, and create libraries and frameworks. This community support makes it easier for website owners to find solutions to common problems and get assistance when needed.
- Compatibility and Integration: PHP is compatible with most web servers and can be easily integrated with other technologies like HTML, CSS, JavaScript, and various content management systems (CMS) such as WordPress, Joomla, and Drupal. This makes it a versatile choice for website owners looking to enhance their websites with dynamic content and functionalities.
- Performance and Speed: PHP is known for its high performance and speed, which is crucial for the user experience. Websites built with PHP can handle large amounts of traffic efficiently, ensuring that visitors have a smooth and responsive experience.
- Security Features: PHP includes several built-in security features that help protect websites from common threats such as SQL injection, cross-site scripting (XSS), and cross-site request forgery (CSRF). By following best practices and utilizing these features, website owners can create secure and robust web applications.
- Frequent Updates: PHP is actively maintained and regularly updated, which ensures that it remains secure, stable, and feature-rich. Staying up-to-date with the latest PHP versions can help website owners take advantage of new functionalities and improvements.
- Cost-Effective Hosting: Many web hosting providers offer affordable PHP hosting plans, making it easier for website owners to find a hosting solution that fits their budget. PHP is also widely supported by most hosting providers, ensuring compatibility and ease of deployment.
- Scalability: PHP is scalable, meaning it can grow with your business. Whether you’re running a small personal blog or a large enterprise-level website, PHP can handle the increased load and complexity as your site expands.
PHP’s affordability, ease of use, versatility, and strong community support make it an essential tool for website owners.
Its ability to integrate with other technologies, provide security, and deliver high performance ensures that websites built with PHP can meet the demands of today’s dynamic and competitive online environment.
How Is PHP Used in WordPress?
PHP (Hypertext Preprocessor) is a powerful scripting language widely used in web development. In the context of WordPress, PHP plays a crucial role as it is the backbone of the entire platform. Here are some ways PHP is used in WordPress:
1: Core PHP Functionality in WordPress
PHP powers the core of WordPress. It handles the server-side logic, including:
- Content Management: PHP scripts manage the creation, retrieval, updating, and deletion of content within the WordPress database.
- User Management: PHP processes user authentication, roles, and permissions.
- Settings and Configuration: PHP loads and processes WordPress settings and configuration files.
2: PHP in WordPress Themes
Themes in WordPress are built using PHP files. These files control the structure and appearance of the website by:
- Template Files: PHP is used in theme template files to dynamically generate HTML content based on the WordPress loop and other template tags.
- Customization: PHP functions allow developers to add custom features and modify existing ones within a theme.
3: PHP in WordPress Plugins
Plugins extend the functionality of WordPress using PHP. They can add new features or modify existing ones by:
- Hooks: PHP hooks (actions and filters) allow plugins to interact with the WordPress core and other plugins/themes.
- Shortcodes: PHP is used to create shortcodes, which can embed dynamic content within posts and pages.
4: PHP for Database Interactions in WordPress
PHP is used to interact with the MySQL database that stores all the data for a WordPress site:
- WPDB Class: The $wpdb class in PHP allows direct database operations, including custom queries.
- CRUD Operations: PHP handles Create, Read, Update, and Delete operations on the WordPress database tables.
5: Custom Post Types and Taxonomies Using PHP
Developers use PHP to create custom post types and taxonomies, extending WordPress beyond posts and pages. This involves:
- Registering Custom Types: PHP functions like register_post_type and register taxonomy are used.
- Meta Boxes: PHP is used to add custom fields and meta boxes to these post types.
6: PHP in the WordPress Admin Dashboard
The WordPress admin dashboard is driven by PHP, providing an interface for site management:
- Menu Pages: Custom admin pages and menus are created using PHP.
- Settings API: PHP handles the creation and management of settings pages and fields.
7: WordPress REST API and PHP
WordPress provides a REST API that uses PHP to handle requests and responses. This API allows developers to:
- Fetch Data: Retrieve posts, users, comments, and other data via HTTP requests.
- Create/Update/Delete Data: Perform CRUD operations through API endpoints.
8: PHP Security in WordPress
PHP is used to implement various security measures in WordPress:
- Data Validation and Sanitization: PHP functions ensure that input data is safe and sanitized before processing.
- Nonce Verification: PHP functions are used to generate and verify nonces to protect against CSRF (Cross-Site Request Forgery) attacks.
PHP is integral to the operation of WordPress, from its core functionality to themes, plugins, and beyond. Understanding PHP is essential for anyone looking to develop or customize a WordPress site.
What Is a PHP Framework?
A PHP framework is a platform that makes it easier for developers to write PHP-based programs. It is made up of code libraries that facilitate typical tasks like data sanitization and form validation.
Compared to writing your original code, this is far faster. However, there are other benefits to utilizing a PHP framework besides speed and ease of use.
Additionally, PHP frameworks provide a simple means of accessing good coding principles. It is essential to learn the WordPress Coding Standards to develop or customize a WordPress Site.
PHP frameworks also promote DRY development, or “Don’t Repeat Yourself,” and the refracting of code. You’ll have an easier-to-maintain, leaner codebase as a result. Moreover, you won’t have to bother about keeping up the basic framework yourself.
PHP frameworks also provide a quick and easy solution to increase the security of your PHP-based apps. A framework may reduce the possibility of hacker attacks, even though you’ll still need to build safe code.
Likewise, some frameworks come with built-in data sanitization defense against common PHP security flaws like cross-site scripting and SQL injections.
Top 3 PHP Frameworks for Web Development
After learning more about the benefits of using PHP frameworks, have a look at some of the top choices.

Firstly, Laravel
Everything you need to create a web application is included with Laravel, including a clean architecture. Numerous capabilities are made possible by it, including file storage, database migration, user authentication, and much more.
Starting with Laravel is also really simple. Installing PHP, a web server, or any other software on your computer is not even necessary. It arrives as a pre-packaged, quick, safe, and lightweight development environment instead.
Second, Symfony
Symfony is a set of PHP components that may be used to create websites as well as a PHP framework. It’s among the most adaptable choices, letting you select the precise parts your project requires.
Additionally, Symfony is compatible with a wide range of databases, such as Oracle, MySQL, and Drizzle. Even better, Sensio Labs is a commercial supporter of Symfony, thus unlike other PHP frameworks, it comes with a wealth of support resources.
Thirdly, CodeIgniter
You can easily set up CodeIgniter because it requires very little configuration. You can add as many components as you like, just as with Symfony. As a result, creating a lightweight application devoid of bloat is simple.
Additionally, CodeIgniter is scalable, helping to shield you from security risks like cross-site scripting. Additionally, there are performance-based features like caching to make your apps run faster.
How to Add PHP Functions Using a WordPress Plugin?
Adding PHP functions using a WordPress plugin is a useful way to extend your WordPress site’s functionality without modifying the core files or theme files, ensuring your changes remain intact through updates.
Here’s a step-by-step guide on how to do it:
Step 1: Create a New WordPress Plugin
1: Access Your WordPress Directory:
- Connect to your WordPress site via FTP or use the file manager in your hosting control panel.
- Navigate to the wp-content/plugins directory.
2: Create a New Folder for Your Plugin:
- Create a new directory and give it a name related to your plugin, e.g., my-custom-functions.
3: Create a PHP File:
- Inside the new directory, create a PHP file with a similar name, e.g., my-custom-functions.php.
Step 2: Add Plugin Information and PHP Functions
1: Open the PHP File:
- Open the my-custom-functions.php file in a text editor.
2: Add the Plugin Header:
- At the top of the file, add the following header information:
<?php
/*
Plugin Name: My Custom Functions
Description: A plugin to add custom PHP functions.
Version: 1.0
Author: Your Name
*/
3: Add Your PHP Functions:
- Below the header, you can start adding your custom PHP functions. For example:
// Example function to display a custom message
function my_custom_message () {
return "Hello, this is a custom message!";
}
// Hooking the function to WordPress init action
add_action ('init', 'my_custom_message');
Step 3: Activate the WordPress Plugin
1: Upload the Plugin Directory:
- If you used FTP, upload the my-custom-functions directory back to the wp-content/plugins directory on your server.
2: Activate the Plugin in WordPress:
- Go to your WordPress admin dashboard.
3: Navigate to Plugins > Installed Plugins.
- Find My Custom Functions and click Activate.
Step 4: Verify the PHP Functionality
1: Test Your Functions:
- Depending on what your functions do, ensure they are working as expected on your site.
For the example function above, you might need to add the function call in a template file or use a shortcode to display it on the site.
- Error Handling: Always add error handling and validation to your functions to avoid breaking your site.
- Security: Sanitize inputs and escape outputs to ensure your functions are secure.
- Documentation: Comment your code to explain what each function does and why you’ve added it.
By following these steps, you can effectively add custom PHP functions to your WordPress site through a plugin, ensuring a modular and maintainable approach to extending your site’s capabilities.
How to Add PHP Functions Without a Plugin? Two Easy ways
A child theme can be the solution if you want to make use of all the advantages of custom PHP without having to install yet another WordPress plugin. We advise making a backup before moving further so you have something to restore if something goes wrong.
You can begin as soon as your backup is set up.
1: Create a Child Theme for PHP Functions
With a client like FileZilla, you can use the File Transfer Protocol (FTP) to create a child theme. Making a directory for your child’s theme is the first thing you need to do when logging into your website.
Create a new folder by browsing to wp-content/themes in FileZilla. We advise utilizing the parent theme’s name, -child added when naming your directory.
Making a style sheet is the next stage. The coding that dictates the layout of your website will be found in this file. Make sure you give this file the filename style. ss when you create it.
You’ll typically need to write a good deal of code to create a child theme that is both visually appealing and functional. However, the WordPress Codex offers some basic code that you can use if you only want to quickly create a child theme to test your new PHP functions:
/*
Theme Name: Twenty Fifteen Child
Theme URI: http://example.com/twenty-fifteen-child/
Description: Twenty Fifteen Child Theme
Author: John Doe
Author URI: http://example.com
Template: twentyfifteen
Version: 1.0.0
License: GNU General Public License v2 or later
License URI: http://www.example.org/licenses/gpl-2.0.html
Tags: light, dark, two-columns, right-sidebar, responsive-layout, accessibility-ready
Text Domain: twentyfifteenchild
*/
To add features to your theme, you’ll next need to create a functions.php file. Open this file in your text editor after it has been created, then add the following:
<?php
add_action (‘wp_enqueue_scripts', 'enqueue_parent_styles' );
function enqueue_parent_styles () {
wp_enqueue_style ('parent-style', get_template_directory_uri ().'/style.css');
}
We are using information from the parent style sheet in this excerpt. You may go to Appearance > Themes in the WordPress dashboard now that you have all the necessary components in place. Your child theme should be visible here. You can activate your theme if you’re satisfied with how it looks.
2: Include a PHP Function in WordPress
Adding your unique PHP functions to your child’s theme is the next step. Access the Theme Editor under Appearance in your WordPress dashboard. Next, select your child theme by opening the Select theme to edit dropdown.
Select the functions.php file from the option on the left. This file is now ready for you to add all of your PHP functions to.
Let’s quickly develop a basic function that will show some text as an example. To do this, copy and paste the content below:
function test_func ($atts) {
return 'This is a PHP function';
}
add_shortcode ('test', 'test_func');
Select the functions.php file from the option on the left. This file is now ready for you to add all of your PHP functions to.
You may use WordPress’s broad feature support to further tweak and expand your new child theme. A full list of all these features may be found in the WordPress Codex.
Why Would You Need a Plugin to Add PHP Functions?
Using plugins to add PHP to a certain webpage can be a quick and simple process. However, installing a whole plugin could seem excessive if you only occasionally need to inject PHP functions.
Another major source of security flaws is WordPress plugins. WP White Security found around 4,000 identified plugin vulnerabilities in 2021. In light of this, you might want to consider reducing the quantity of plugins that are set up on your WordPress website.
As we’ve shown, by developing a child theme, you may manually insert PHP. The functions.php file for that child is then where you can add your custom code. The disadvantage is that this specific theme is the only one on which your PHP functions will function.
It’s usually preferable to establish a child theme before adding your PHP code to your existing theme, despite the temptation to do so. Every time you update your theme, any modifications you make directly to the functions.php file of the parent theme will be overwritten.
Now that you’ve taken the time to make a child theme, you can keep applying the most recent upgrades without worrying about losing any of your customized code.
Conclusion
A successful WordPress website may be operated without any knowledge of PHP. On the other hand, PHP can be a useful tool for expanding and improving the fundamental Content Management System (CMS) framework.
If you know a little PHP, you can add your own unique hooks to any post or page. Additionally, you can modify your preferred plugins and themes to make them ideal for your WordPress website. If you’re up for the challenge, learning PHP can even be the first step toward creating your own plugins and themes.
Your website may benefit greatly from custom PHP. Malware might attempt to use this programming language as a weapon against you, though.
Here at ARZ Host, we provide all the security protections you require to benefit risk-free with bespoke PHP.
FAQs (Frequently Asked Questions)
1: What is PHP?
PHP, which stands for “Hypertext Preprocessor,” is a widely-used, open-source server-side scripting language designed for web development. It can also be embedded into HTML, which allows for dynamic content generation and interaction with databases. PHP is executed on the server, generating HTML that is then sent to the client’s browser. This makes PHP highly effective for creating dynamic web pages and applications.
2: How does PHP work on a server?
When a user requests a web page that contains PHP code, the server processes this code using the PHP interpreter. The PHP script runs on the server, which may involve querying a database, processing data, or performing other server-side tasks.
After executing the PHP code, the server generates HTML (or other formats) and sends this output to the user’s browser. The browser only sees the resulting HTML and does not have access to the PHP code.
3: Why is PHP popular for web development?
PHP is popular for several reasons:
- Ease of Use: PHP is relatively easy to learn and use, with a simple syntax that is similar to other programming languages.
- Flexibility: It can be integrated with various databases, including MySQL, PostgreSQL, and SQLite, and can be used on multiple platforms like Windows, Linux, and macOS.
- Open Source: PHP is free to use and has a large community that contributes to its development and provides support.
- Strong Integration with HTML: PHP can be embedded directly into HTML, allowing developers to easily create dynamic web pages.
- Large Ecosystem: It has a rich set of frameworks, libraries, and tools, including popular content management systems (CMS) like WordPress.
4: How does PHP power WordPress?
WordPress, a leading content management system (CMS), is built on PHP. Here’s how PHP plays a role in WordPress:
- Dynamic Content Generation: WordPress uses PHP to dynamically generate web pages based on user interactions and database content. PHP scripts pull data from the database and insert it into HTML templates to create the final web pages.
- Database Interaction: PHP interacts with the MySQL database used by WordPress to store and retrieve content, user information, and settings. PHP executes SQL queries to manage this data and render it in WordPress themes and plugins.
- Theme and Plugin Development: WordPress themes and plugins are developed using PHP. Custom functionality and design elements are implemented through PHP code, which integrates seamlessly with the WordPress core to extend its capabilities.
- Server-Side Logic: PHP handles server-side tasks such as user authentication, content management, and form processing. This logic ensures that WordPress websites function correctly and securely.
5: Can I use PHP without WordPress?
Yes, PHP can be used independently of WordPress. It is a versatile language that can be utilized to build a wide range of web applications and websites. Developers can write custom PHP scripts for various purposes, such as creating web forms, handling file uploads, developing e-commerce sites, or building custom content management systems.
While WordPress is a popular platform that leverages PHP, the language’s capabilities extend far beyond WordPress, offering flexibility and power for numerous web development projects.
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