Which language is primarily used for creating interactive elements on web pages?

JavaScript is the primary language used for creating interactive elements on web pages because it enables developers to implement dynamic functionalities that respond to user actions. Unlike HTML, which is responsible for structuring content, and CSS, which is utilized for styling, JavaScript adds behavior to web pages. It allows for tasks such as form validation, creating image sliders, and handling events like mouse clicks or keyboard inputs, thus enhancing user engagement and experience.

PHP, although it can be used to create dynamic web pages on the server side, does not directly handle interactivity in the client's browser like JavaScript does. Therefore, when it comes to immediate user interactions that update or modify the content without requiring a page refresh, JavaScript is the appropriate choice. Its versatility and ability to manipulate the Document Object Model (DOM) make it essential for achieving interactivity in modern web applications.