In today’s web development ecosystem, employers look for professionals who can seamlessly work across front-end scripting, server-side logic, databases, and CMS customization. JavaScript, PHP, MySQL, and WordPress together form a powerful and widely used full-stack combination.
This blog covers the Top 25 most frequently asked interview questions with clear, practical answers, helping you crack interviews for Web Developer, WordPress Developer, PHP Developer, and Full-Stack roles.
JavaScript is a client-side scripting language used to create dynamic and interactive web pages. It allows developers to handle events, validate forms, manipulate the DOM, and communicate with servers using AJAX or APIs. Today, JavaScript is also used on the server side through Node.js, making it a full-stack language.
var, let, and const?Best practice is to use let and const to avoid unexpected bugs.
The Document Object Model (DOM) is a programming interface that represents HTML as a tree structure. JavaScript uses the DOM to dynamically change content, styles, and structure of a webpage without reloading it.
Event bubbling means that an event triggered on a child element propagates upward to its parent elements. JavaScript allows control over this behavior using event.stopPropagation().
A closure is a function that remembers variables from its outer scope even after the outer function has executed. Closures are commonly used for data privacy and function factories.
JSON (JavaScript Object Notation) is a lightweight data interchange format used for sending data between client and server. It is easy to read, write, and parse.
AJAX (Asynchronous JavaScript and XML) allows web pages to fetch data from the server without reloading the page, improving user experience and performance.
PHP is a server-side scripting language used to build dynamic websites and web applications. It is widely used with CMS platforms like WordPress and frameworks such as Laravel.
echo and print?Both are used to display output in PHP.
Sessions are more secure and commonly used for authentication.
include and require?Use require for critical files.
PDO (PHP Data Objects) is a secure database access layer that supports prepared statements, preventing SQL injection attacks.
Prepared statements separate SQL logic from data, improving security and performance when executing database queries multiple times.
PHP supports error handling using try, catch, custom error handlers, and logging errors to files instead of displaying them to users.
MySQL is an open-source relational database management system (RDBMS) used to store structured data for web applications.
DELETE, TRUNCATE, and DROP?They ensure data integrity.
Normalization is the process of organizing data to reduce redundancy and improve data consistency by dividing tables logically.
Indexing improves query performance by allowing faster data retrieval, similar to an index in a book.
WordPress is an open-source content management system (CMS) built using PHP and MySQL. It is used for blogs, websites, and eCommerce stores.
Custom development often involves modifying both.
A child theme inherits functionality from a parent theme and allows safe customization without losing changes during updates.
Hooks allow developers to modify WordPress behavior without changing core files.
A custom plugin is created by:
/wp-content/pluginsMastering JavaScript, PHP, MySQL, and WordPress Customization gives you a strong advantage in full-stack and CMS-based development roles. These 25 interview questions and answers cover both theoretical concepts and practical knowledge, making them ideal for interviews in web development agencies, startups, and enterprises.
If you are preparing for interviews, revise these questions, practice coding examples, and build small projects to strengthen your confidence.