4-11 编程练习作业提交

来源：4-11 编程练习

我在浪费钱

2021-09-23 18:08:06

<!DOCTYPE html>
<html>

<head lang="en">
    <meta charset="UTF-8">
    <title>onblur和onfocus</title>
    <style type="text/css">
        .red {
            border: 1px solid red;
        }
    </style>
</head>

<body>
    姓名：<input type="text" id="input"> <span id="tips"></span>
    <script type="text/javascript">
        // 补充代码
        input = document.getElementById('input');
        tips = document.getElementById('tips');

        input.onfocus = function () {
            tips.innerHTML = '请输入您的大名';
        }
        input.onblur = function () {
            value = this.value;
            if (value.length == 0) {
                tips.innerHTML = '用户名不能为空';
            } else {
                tips.innerHTML = '';
            }
        }
    </script>
</body>

</html>