一个不常用的DOM原生API，closest

1.closest

1.1 功能详解

功能：返回当前节点最近的匹配选择符的祖先元素

var el = document.querySelector(childSelector).closest(parentSelector);

如下网页结构：

<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>closest</title>
    </head>
    <body>
        <div class="con">
            <span class="list"></span>
        </div>
    </body>
</html>

1.1.1 比如想要通过.list来选取.con

document.querySelector('.list').closest('.con');

结果：会返回.con元素

1.1.2 如果childSelector参数和parentSelector参数相同

document.querySelector('.list').closest('.list');

结果：会返回.list元素

1.1.3 如果parentSelector没找到

document.querySelector('.list').closest('.tip');

结果：会返回null

1.2 应用案例

需求说明：用事件委托来获取当前点击区块的data-option值

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
    <div class="con">
        <div class="con-list" data-option="1">
            <span class="con-list-name">小明</span>
            <span class="con-list-gender">男</span>
        </div>
        <div class="con-list" data-option="2">
            <span class="con-list-name">小华</span>
            <span class="con-list-gender">男</span>
        </div>
        <div class="con-list" data-option="3">
            <span class="con-list-name">小美</span>
            <span class="con-list-gender">女</span>
        </div>
    </div>
    <script>
        document.querySelector('.con').addEventListener('click', function(e) {
            console.log(e.target.closest('.con-list').dataset.option);
        })
    </script>
</body>
</html>
posted @ 2018-09-28 16:46  cococe  阅读(94)  评论(0)  编辑  收藏  举报