JS全选单选按钮案例-CFANZ编程社区

案例展示

HTML/CSS部分

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        * {
            padding: 0;
            margin: 0;
        }
        
        .wrap {
            width: 300px;
            margin: 100px auto 0;
        }
        
        table {
            border-collapse: collapse;
            border-spacing: 0;
            border: 1px solid #c0c0c0;
            width: 300px;
        }
        
        th,
        td {
            border: 1px solid #d0d0d0;
            color: #404060;
            padding: 10px;
        }
        
        th {
            background-color: #09c;
            font: bold 16px "微软雅黑";
            color: #fff;
        }
        
        td {
            font: 14px "微软雅黑";
        }
        
        tbody tr {
            background-color: #f0f0f0;
        }
        
        tbody tr:hover {
            cursor: pointer;
            background-color: #fafafa;
        }
    </style>
</head>
<body>
    <div class="wrap">
        <table>
            <thead>
                <tr>
                    <th>
                        <input type="checkbox" id="j_cbAll" />
                    </th>
                    <th>商品</th>
                    <th>价钱</th>
                </tr>
            </thead>
            <tbody id="j_tb">
                <tr>
                    <td>
                        <input type="checkbox" />
                    </td>
                    <td>iPhone8</td>
                    <td>8000</td>
                </tr>
                <tr>
                    <td>
                        <input type="checkbox" />
                    </td>
                    <td>iPad Pro</td>
                    <td>5000</td>
                </tr>
                <tr>
                    <td>
                        <input type="checkbox" />
                    </td>
                    <td>iPad Air</td>
                    <td>2000</td>
                </tr>
                <tr>
                    <td>
                        <input type="checkbox" />
                    </td>
                    <td>Apple Watch</td>
                    <td>2000</td>
                </tr>

            </tbody>
        </table>
    </div>
</body>
</html>

JavaScript部分

        //1.首先获取input元素
        var j_cbAll = document.getElementById('j_cbAll') //全选按钮
        var j_tbs = document.getElementById('j_tb').querySelectorAll('input')
        
        //2.给全选按钮注册事件
        j_cbAll.onclick = function() {
            for (var i = 0; i < j_tbs.length; i++) {
                j_tbs[i].checked = this.checked;
            }
        }

        //给复选按钮注册事件
        for (var i = 0; i < j_tbs.length; i++) {
            j_tbs[i].onclick = function () {

 //定义一个变量，用来控制全选按钮,默认是选中状态
                var flag = true;
       //定义循环变量i，与外层for循环的i相同，是因为内层被函数包裹，作用域不同
                for (var i = 0; i <j_tbs.length; i++) {
       //当复选按钮里有一个选中状态是false，flag改为false，并退出循环
                    if (j_tbs[i].checked == false) {
                        flag = false;
                        break;
                    }
                }
                
                j_cbAll.checked = flag;
            }
        }