The auxclick event is fired at an Element when a non-primary pointing device button (any mouse button other than the primary—usually leftmost—button) has been pressed and released both within the same element.
auxclick is fired after the mousedown and mouseup events have been fired, in that order.
Syntax
Use the event name in methods like addEventListener(), or set an event handler property.
Note: In earlier versions of the specification the event type for this event was a MouseEvent, and this is still the type passed in Firefox and Safari.
Event properties
This interface also inherits properties of its parents, UIEvent and Event.
The type of device that generated the event (one of the MOZ_SOURCE_* constants). This lets you, for example, determine whether a mouse event was generated by an actual mouse or by a touch event (which might affect the degree of accuracy with which you interpret the coordinates associated with the event).
The normalized pressure of the pointer input in the range 0 to 1, where 0 and 1 represent the minimum and maximum pressure the hardware is capable of detecting, respectively.
The normalized tangential pressure of the pointer input (also known as barrel pressure or cylinder stress) in the range -1 to 1, where 0 is the neutral position of the control.
The plane angle (in degrees, in the range of -90 to 90) between the Y–Z plane and the plane containing both the pointer (e.g. pen stylus) axis and the Y axis.
The plane angle (in degrees, in the range of -90 to 90) between the X–Z plane and the plane containing both the pointer (e.g. pen stylus) axis and the X axis.
Indicates if the pointer represents the primary pointer of this pointer type.
Preventing default actions
For the vast majority of browsers that map middle click to opening a link in a new tab, including Firefox, it is possible to cancel this behavior by calling preventDefault() from within an auxclick event handler.
When listening for auxclick events originating on elements that do not support input or navigation, you will often want to explicitly prevent other default actions mapped to the down action of the middle mouse button. On Windows this is usually autoscroll, and on macOS and Linux this is usually clipboard paste. This can be done by preventing the default behavior of the mousedown or pointerdown event.
Additionally, you may need to avoid opening a system context menu after a right click. Due to timing differences between operating systems, this too is not a preventable default behavior of auxclick. Instead, this can be done by preventing the default behavior of the contextmenu event.
Examples
In this example we define functions for two event handlers — onclick and onauxclick. The former changes the color of the button background, while the latter changes the button foreground (text) color. You also 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).
JavaScript
js
let button = document.querySelector("button");let html = document.querySelector("html");functionrandom(number){return Math.floor(Math.random()* number);}functionrandomColor(){return`rgb(${random(255)}, ${random(255)}, ${random(255)})`;}
button.onclick=()=>{
button.style.backgroundColor =randomColor();};
button.onauxclick=(e)=>{
e.preventDefault();
button.style.color =randomColor();};
button.oncontextmenu=(e)=>{
e.preventDefault();};
Notice that in addition to capturing the auxclick event using onauxclick, the contextmenu event is also captured, and preventDefault() called on that event, in order to prevent the context menu from popping up after the color change is applied.
HTML
html
<button><h1>Click me!</h1></button>
Note: If you are using a three-button mouse, you'll notice that the onauxclick handler is run when any of the non-left mouse buttons are clicked (usually including any "special" buttons on gaming mice).
53Starting in Firefox 68, the auxclick event is used to trigger the new tab on middle-click action; previously, this had been done with the click event. Apps can prevent middle-click from opening new tabs (or middle-click to paste, if that feature is enabled) by intercepting auxclick on links, and auxclick event handlers can now open popups without triggering the popup blocker.