Several programming languages are commonly used in web application development. JavaScript is widely used for frontend development, providing interactive user interfaces using frameworks like React and Angular. Python, known for its readability, is widely used in backend development with frameworks such as Django. Java, a versatile language, is used for both frontend and backend development, often using frameworks such as Spring (Java EE). PHP is commonly used for server-side scripting with frameworks like Laravel and Symfony. Ruby emphasizes simplicity and performance and is used for backend development, with Ruby on Rails being prominent among them.