MouseEvent.which

Non-standard
This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.

The MouseEvent.which read-only property indicates which button was pressed on the mouse to trigger the event. The standard alternatives to this property are MouseEvent.button and MouseEvent.buttons.

Syntax

var buttonPressed = instanceOfMouseEvent.which

Return value

A number representing a given button:

  • 0: No button
  • 1: Left button
  • 2: Middle button (if present)
  • 3: Right button

For a mouse configured for left-handed use, the button actions are reversed. In this case, the values are read from right to left.

Specification

This is not part of any specification.

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidiOS SafariSamsung Internet
Basic support
Non-standard
Chrome Full support 1Edge Full support YesFirefox Full support 1
Notes
Full support 1
Notes
Notes On mousemove events, the which property is incorrectly always set to 1.
IE Full support 9Opera Full support 5Safari Full support 1WebView Android Full support YesChrome Android Full support YesEdge Mobile Full support YesFirefox Android Full support 4
Notes
Full support 4
Notes
Notes On mousemove events, the which property is incorrectly always set to 1.
Opera Android Full support YesSafari iOS Full support YesSamsung Internet Android ?

Legend

Full support  
Full support
Compatibility unknown  
Compatibility unknown
Non-standard. Expect poor cross-browser support.
Non-standard. Expect poor cross-browser support.
See implementation notes.
See implementation notes.

See also

Document Tags and Contributors

Contributors to this page: fscholz, libbymc, Ac1521, cvrebert, Sebastianz, teoli, Marijn
Last updated by: fscholz,