How and why to use JavaScript media queries

Media queries, introduced in CSS3, are essential for responsive web design, enabling applications to adjust to various device constraints by setting viewport dimensions and altering style properties based on screen size. While CSS media queries are widespread, JavaScript media queries offer additional flexibility and advantages, such as programmatically incorporating conditions and triggering events. This can be particularly useful in avoiding the performance issues associated with CSS-only approaches, which respond to every screen resize event. The matchMedia API in JavaScript provides a more efficient way to handle media queries by allowing developers to execute logic only when specific screen conditions are met, without responding to every window or screen size change. This API returns a MediaQueryList object, enabling event-driven and immediate matching, and can be paired with the addListener() method to dynamically invoke methods and alter document properties in response to media query changes. This approach improves the efficiency and responsiveness of web applications by focusing on specific changes rather than constant polling.