MediaQueryListEvent.matches

The matches read-only property of the MediaQueryListEvent interface is a Boolean that returns true if the document currently matches the media query list, or false if not.

var matches = MediaQueryListEvent.matches;

A Boolean; returns true if the document currently matches the media query list, false if not.

var mql = window.matchMedia('(max-width: 600px)');

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

mql.addListener(screenTest);

• Media queries
• Using media queries from code
• window.matchMedia()
• MediaQueryList
• MediaQueryListEvent