contextmenu.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        ul{
            margin: 0;
            padding: 0;
        }
        li{
            list-style: none;
        }
        .contextmenu{
            width: 200px;
            border: solid 1px #0000FF;
            display: none;
            position: absolute;
        }
        .contextmenu li{
            width: 200px;
            line-height: 30px;
            text-align: center;
            background: #DDD;
            margin: 10px 0;
        }
        .contextmenu li:hover{
            background: #4D4D4D;
        }
    </style>
</head>
<body>
<ul class="contextmenu">
    <li>1</li>
    <li>2</li>
    <li>3</li>
    <li>4</li>
    <li>5</li>
</ul>
<script>
    const contextmenu = document.getElementsByClassName('contextmenu')[0];

    window.addEventListener('contextmenu',function (ev) {
        contextmenu.style.display = 'block';
        contextmenu.style.top = ev.pageY + 'px';
        contextmenu.style.left = ev.pageX + 'px';
        ev.preventDefault();  //阻止默认右键菜单出现
    })

    contextmenu.onclick = function (ev) {
        if(ev.target.tagName === 'LI'){
            console.log(ev.target);
        }
        ev.cancelBubble = true;  //阻止冒泡，否则菜单点击会触发window的点击事件，菜单会消失
    }

    window.onclick = function (ev) {
        contextmenu.style.display = 'none';
    }
</script>
</body>
</html>