javascript - When deleting DOM using removechild, you need to get the parent element first, but when insertbefore, you don't need to go to the parent element. and can be used directly
<!DOCTYPE HTML>
<html lang="en-US">
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>
<button id='btn'>创建元素</button>
<script type="text/javascript">
var btn = document.getElementById('btn');
//注册点击事件
btn.onclick = function(){
//创建一个元素
var h1 = document.createElement('h1');
h1.innerHTML = "这是新增h1标签";
console.log( h1 );
//使用appendChild的方式
//document.body.appendChild( h1 );
//使用insertBefore的方式
//是在父元素中，先找一个节点，然后插入到它之前
document.body.insertBefore(h1,btn); //新插入的节点是h1，作为第一个参数
}
</script>
</body>
</html>
<!DOCTYPE HTML>
<html lang="en-US">
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>
<p id="box">
<h2>删除操作</h2>
<p>段落1</p>
</p>
<button id='btn'>删除</button>
<script type="text/javascript">
//找父节点p
//var box = document.getElementById('box');
//找子节点h2
var h2 = document.getElementsByTagName('h2')[0];
var btn = document.getElementById('btn');
btn.onclick = function() {
//box.removeChild( h2 );
h2.parentNode.removeChild( h2 );
}
</script>
</body>
</html>
