用户验证案列

原创于 2024-12-27 21:05:57 发布 · 101 阅读

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<!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>
        span {
            display: inline-block;
            width: 250px;
            height: 30px;
            vertical-align: middle;
            line-height: 30px;
            padding-left: 15px;
        }

        .error {
            color: red;
            background: url(./images/error1.png) no-repeat left center;
        }

        .right {
            color: green;
            background: url(./images/right.png) no-repeat left center;
        }
    </style>
</head>

<body>
    <input type="text">
    <span></span>
    <script>
        // 规定正则表达式
        const reg = /^[a-zA-Z0-9-_]{6,16}$/
        // 获取元素
        const input = document.querySelector('input')
        const span = input.nextElementSibling
        // 当表单失去焦点时开始验证
        input.addEventListener('blur', function () {
            if (reg.test(input.value)) {
                span.innerHTML = '输入正确'
                span.className = 'right'
            } else {
                span.innerHTML = '请输入6-16位的字母数字或-_'
                span.className = 'error'

            }
        })
    </script>
</body>

</html>