js4-1

by wang_siang

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/autosize.js/3.0.20/autosize.min.js"></script>
<form action="">
        <input type="text" name="" id="" placeholder="請輸入暱稱">
        <textarea name="" id="myTextarea" placeholder="請輸入留言"></textarea>
        <button type="submit" id="submit" onclick="prevent(event)">送出</button>
    </form>

CSS

* {
            box-sizing: border-box;
        }

        body {
            margin: 0;
        }

        form {
            width:fit-content;
            margin: 80px auto;
            padding: 40px;
            display: flex;
            flex-direction: column;
            gap: 18px;
            box-shadow: 0px 0px 8px 5px rgba(175, 175, 175, 0.26);
            border-radius: 20px;
        }

JavaScript

autosize(document.querySelector('#myTextarea'));
        
        function prevent(e){
            e.preventDefault();
        }