GlobalEventHandlers.onauxclick

The onauxclick property is an EventHandler called when an auxclick event is sent, indicating that a non-primary button has been pressed on an input device (e.g. a middle mouse button).

This property is implemented as part of a plan to improve compatibility between browsers with regards to button behaviours — event behaviour is being updated so that click only fires for primary button clicks (e.g. left mouse button). Developers can then use auxclick to provide explicit behaviour for non-primary button clicks. Previous to this, click generally fired for clicks on all input device buttons, and browser behaviour was somewhat inconsistent.

Syntax

element.onauxclick = functionRef(e);

The event handler function is a MouseEvent object. Apart from the button(s) the event is fired on, the behaviour is exactly the same.

Example

In this example we define two event handler functions — onclick and onauxclick. The former changes the color of the button background, while the latter changes the button foreground (text) color. You can see the two functions in action by trying the demo out with a multi-button mouse (see it live on GitHub; also see the source code).

var button = document.querySelector('button');
var html = document.querySelector('html');
function random(number) {
  return Math.floor(Math.random() * number);
}
button.onclick = function() {
  var rndCol = 'rgb(' + random(255) + ',' + random(255) + ',' + random(255) + ')';
  button.style.backgroundColor = rndCol;
};
button.onauxclick = function() {
  var rndCol = 'rgb(' + random(255) + ',' + random(255) + ',' + random(255) + ')';
  button.style.color = rndCol;
}

Notes

The click event is raised when the user clicks on an element. The click event will occur after the mousedown and mouseup events.

Only one click handler can be assigned to an object at a time with this property. You may be inclined to use the EventTarget.addEventListener() method instead, since it is more flexible and part of the DOM Events specification.

Specification

onauxclick is not part of any official specification yet; the definition can be found in the auxclick Draft Community Group Report.

Browser Compatibility