js

removeListener(func)

js

const paragraph = document.querySelector("p");
const mediaQueryList = window.matchMedia("(max-width: 600px)");

function screenTest(e) {
  if (e.matches) {
    /* the viewport is 600 pixels wide or less */
    paragraph.textContent = "This is a narrow screen — 600px wide or less.";
    document.body.style.backgroundColor = "pink";
  } else {
    /* the viewport is more than 600 pixels wide */
    paragraph.textContent = "This is a wide screen — more than 600px wide.";
    document.body.style.backgroundColor = "aquamarine";
  }
}

mediaQueryList.addListener(screenTest);

// Later on, when it is no longer needed
mediaQueryList.removeListener(screenTest);