MouseEvent.button

MouseEvent.button 返回一个数值，代表用户按下的鼠标按键，正是此按键触发了事件；只读属性。

这个属性只能够表明在事件中通过按下或者放开一个按键，或者是多个按键同时按下时，哪一个按键被按下。因此，它对判断mouseenter, mouseleave, mouseover, mouseout or mousemove这些事件并不可靠。

Users may change the configuration of buttons on their pointing device so that if an event's button property is zero, it may not have been caused by the button that is physically left–most on the pointing device; however, it should behave as if the left button was clicked in the standard button layout.

语法

var buttonPressed = instanceOfMouseEvent.button

返回值

一个数值，代表按下的鼠标按键：

• 0：主按键被按下，通常指鼠标左键 or the un-initialized state
• 1：辅助按键被按下，通常指鼠标滚轮 or the middle button (if present)
• 2：次按键被按下，通常指鼠标右键
• 3：第四个按钮被按下，通常指浏览器后退按钮
• 4：第五个按钮被按下，通常指浏览器的前进按钮

对于配置为左手使用的鼠标，按键操作将正好相反。此种情况下，从右至左读取值。

Example

<script>
var whichButton = function (e) {
    // Handle different event models
    var e = e || window.event;
    var btnCode;
    if ('object' === typeof e) {
        btnCode = e.button;
        switch (btnCode) {
            case 0:
                console.log('Left button clicked.');
            break;
            case 1:
                console.log('Middle button clicked.');
            break;
            case 2:
                console.log('Right button clicked.');
            break;
            default:
                console.log('Unexpected code: ' + btnCode);
        }
    }
}
</script>
<button onmouseup="whichButton(event);" oncontextmenu="event.preventDefault();">Click with mouse...</button>

Specifications

Browser compatibility

[1] This convention is not followed in Internet Explorer prior to version 9: see QuirksMode for details.

See also

• "MouseEvent"