MediaQueryList.addListener()

The addListener() method of the MediaQueryList interface adds a listener to the MediaQueryListener that will run a custom callback function in response to the media query status changing.

This is basically an alias for EventTarget.addEventListener(), for backwards compatibility purposes — in older browsers you could use addEventListener instead.

Syntax

MediaQueryList.addListener(func)

Parameters

func

A function or function reference representing the callback function you want to run when the media query status changes. In the original implementation, the callback was a non-standard MediaQueryListListener object. In the new implementation the standard event mechanism is used, the callback is a standard function, and the event object is a MediaQueryListEvent, which inherits from Event.

Return value

Void.

Examples

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);

Specifications

Browser compatibility

See also

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