!doctype html html lang="en" head meta charset="UTF-8" titlediv模拟textarea文本域轻松实现高度自适应/title style h2 { text-align: center; margin: 50px auto; } .test_box { width: 400px; min-height: 20px; /*设置最小高度*/ m
          <!doctype html>
<html lang="en">
<head>
 <meta charset="UTF-8">
 <title>div模拟textarea文本域轻松实现高度自适应</title>
 <style>
 h2 {
 text-align: center;
 margin: 50px auto;
 }
 .test_box {
 width: 400px;
 min-height: 20px;
 /*设置最小高度*/
 max-height: 500px;
 /*设置最大高度超过300px时出现滚动条*/
 _height: 120px;
 margin-left: auto;
 margin-right: auto;
 padding: 13px;
 outline: 0;
 border: 1px solid #a0b3d6;
 font-size: 16px;
 line-height: 24px;
 word-wrap: break-word;
 overflow-x: hidden;
 overflow-y: auto;
 border-color: rgba(82, 168, 236, 0.8);
 box-shadow: inset 0 1px 3px rgba(0, 0, 0, 0.1), 0 0 8px rgba(82, 168, 236, 0.6);
 }
 </style>
</head>
<body>
<h2>div模拟textarea文本域轻松实现高度自适应</h2>
<div class="test_box" contenteditable="true">
 <br />
</div>
</body>
</html>
