2.26.2-练习:文本框输入文字,在旁边放大提示效果

练习2 输入文字字体放大再提示


<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Documenttitle>
    <style>
        * {
            margin: 0;
            padding: 0;
        }
        
        .box {
            width: 300px;
            margin: 0 auto;
            position: relative;
        }
        
        p {
            width: 200px;
            height: 30px;
            margin-top: 50px;
        }
        
        #enlarge {
            width: 200px;
            height: 30px;
            font-size: 16px;
            line-height: 30px;
            display: none;
            background-color: greenyellow;
            position: absolute;
            top: 0;
        }
        
        span {
            display: block;
            height: 0;
            width: 0;
            border: 11px solid transparent;/*transparent 颜色透明*/
            border-top-color: greenyellow;
            position: absolute;
            top: 30px;
            left: 50px;
        }
        
        input {
            outline: none;
            width: 200px;
            height: 20px;
            margin-top: 12px;
        }
    style>
head>

<body>
    <div class="box">
        <p>请输入你想输入的内容p>
        <div id="enlarge">
            <span>span>
        div>
        <input type="text">
    div>
    <script>
        var inp = document.querySelector('input');
        var enlarge = document.querySelector('#enlarge');
        //聚焦到输入框
        inp.onfocus = function() {
            //键盘输入值
            document.addEventListener('keyup', function(e) {
                console.log(e.key);
                
                if (inp.value === '') {
                    enlarge.style.display = 'none';
                } else {
                    enlarge.style.display = 'block';
                enlarge.innerHTML = inp.value + "";
                }
                
            });
        }
    script>
body>

html>

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