MediaQueryList.onchange

The onchange property of the MediaQueryList interface is an event handler property representing a function that is invoked when the change event fires, i.e when the status of media query support changes. The event object is a MediaQueryListEvent instance, which is recognized as a MediaListQuery instance in older browsers, for backwards compatibility purposes.

MediaQueryList.onchange = function() { ... };

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

mql.addEventListener( "change", (e) => {
    if (e.matches) {
    /* the viewport is 600 pixels wide or less */
    console.log('This is a narrow screen — less than 600px wide.')
  } else {
    /* the viewport is more than than 600 pixels wide */
    console.log('This is a wide screen — more than 600px wide.')
  }
})

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