如何让pre和textarea等HTML元素去掉滚动条自动换行自适应文本内容高度

<pre>ourjs this is very very very very very very very very very very very very very very very logn contents.</pre>pre {    word-wrap: break-word;    white-space: pre-wrap;    padding: 9.5px;    background-color: #f5f5f5;    border: 1px solid #ccc;}

var textarea = document.getElementsByTagName('textarea')[0];textarea.setAttribute('style','height:'+(textarea.scrollHeight + 12)+'px');