引入autosize.js
<script src="./autosize.js"></script>
autosize(document.getElementsByTagName(‘textarea‘)); var textareas = document.getElementsByTagName(‘textarea‘); for (var i =0;i<textareas.length;i++){ textareas[i].style.minHeight="60px"; }
下载地址
https://www.bootcdn.cn/autosize.js/
原文：https://www.cnblogs.com/mlh1421/p/11968811.html