MouseEvent button Property

Find out which mouse button that was pressed when a mouse event was triggered:

alert("You pressed button: " + event.button)

Definition and Usage

The button property returns a number that indicates which mouse button was pressed when a mouse event was triggered.

This property is mostly used together with the onmousedown event.

Note: This property is read-only.

The numbers in the table specify the first browser version that fully supports the property.

Property
button	Yes	Yes	Yes	Yes	8.0

event.button

Return Value:	A Number, representing which mouse button that was pressed when the mouse event occured. Possible values: 0 : Left mouse button 1 : Wheel button or middle button (if present) 2 : Right mouse button Note: Internet Explorer 8 and earlier has different return values: 1 : Left mouse button 2 : Right mouse button 4 : Wheel button or middle button (if present) Note: For a left-hand configured mouse, the return values are reversed
DOM Version:	DOM Level 2 Events

Return Value:

A Number, representing which mouse button that was pressed when the mouse event occured.

Possible values:

Note: Internet Explorer 8 and earlier has different return values:

Note: For a left-hand configured mouse, the return values are reversed

DOM Version:

DOM Level 2 Events