简单留言板发言
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
ul {
background-color: springgreen;
}
</style>
</head>
<body>
<textarea name="" id="" cols="30" rows="10">123</textarea>
<button>发布</button>
<ul>
</ul>
<script>
//1.获取元素
var btn = document.querySelector(‘button‘);
var text = document.querySelector(‘textarea‘);
var ul = document.querySelector(‘ul‘);
//2.注册事件
btn.onclick = function() {
//(1)创建元素
if(text.value == ‘‘){
alert(‘您没有输入‘);
return false;
}else{
var li = document.createElement(‘li‘);
//(2)添加元素
// ul.appendChild(li);
ul.insertBefore(li,ul.children[0]);
//现有li
li.innerHTML = text.value;//inner
}
}
</script>
</body>
</html>
原文：https://www.cnblogs.com/qiujie-prion/p/13031593.html