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一個不常用的DOM原生API,closest

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1.closest

1.1 功能詳解

功能:返回當前節點最近的匹配選擇符的祖先元素

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

如下網頁結構:

<!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 比如想要通過.list來選取.con

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

結果:會返回.con元素

1.1.2 如果childSelector參數和parentSelector參數相同

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

結果:會返回.list元素

1.1.3 如果parentSelector沒找到

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

結果:會返回null

1.2 應用案例

需求說明:用事件委托來獲取當前點擊區塊的data-option

<!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">小華</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>

一個不常用的DOM原生API,closest