The MouseEvent.buttons read-only property indicates which buttons were pressed on the mouse to trigger the event.

Each button that can be pressed is represented by a given number (see below). If more than one button is pressed, the value of the buttons is combined to produce a new number. For example, if the right button (2) and the wheel button (4) are pressed, the value is equal to 2|4, which is 6.

Note: Do not confuse this property with the MouseEvent.button property.


var buttonPressed = instanceOfMouseEvent.buttons

Return value

A number representing one or more buttons. For more than one button pressed, the values are combined.

  • : Left button
  • : Right button
  • : Wheel button or middle button
  • : 4th button (typically the "Browser Back" button)
  • 16 : 5th button (typically the "Browser Forward" button)


Specification Status Comment
Document Object Model (DOM) Level 3 Events Specification
The definition of 'MouseEvent.buttons' in that specification.
Working Draft Initial definition.

Browser compatibility

Feature Firefox (Gecko) Chrome Internet Explorer Opera Safari
Basic support 38 (likely earlier) 43 ( 9 (Yes) (Yes)
Feature Firefox Mobile (Gecko) Android IE Mobile Opera Mobile Safari Mobile
Basic support ? ? ? ? ?

Gecko notes

Gecko supports the buttons attribute on Windows, Linux (GTK), and Mac with the following restrictions:

  • On Windows, if you install a mouse driver, and its utility software allows you to customize button actions (e.g., IntelliPoint and SetPoint), the middle (wheel) button, the 4th button, and the 5th button might not be set, even when they are pressed.
  • On Linux (GTK), the 4th button and the 5th button are not supported. In addition, a mouseup event always has the releasing button information in this attribute value.
  • On Mac OS X 10.5, the buttons attribute always returns 0 because there is no platform API for implementing this feature.

See also

Document Tags and Contributors

Last updated by: michaelbaur,