1.代码
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>title</title>
<style>
div{
width: 300px;
height: 200px;
border:2px solid pink;
}
</style>
</head>
<body>
<input type="button" value="创建一个p" id="btn" />
<div id="dv"></div>
<script>
//点击按钮在div中创建一个p标签
//第二种方式创建元素：对象.innerHTML="标签代码及内容";
document.getElementById("btn").onclick = function(){
document.getElementById("dv").innerHTML="<P>何当共剪西窗烛，却话巴山夜雨时</P>";
};
</script>
</html>